HARBINGER CORP
S-3/A, 1997-07-28
COMPUTER PROGRAMMING, DATA PROCESSING, ETC.
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<PAGE>   1
 
   
     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JULY 28, 1997
    
                                                      REGISTRATION NO. 333-31191
================================================================================
 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                             ---------------------
   
                                AMENDMENT NO. 2
    
                                       TO
 
                                    FORM S-3
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
                             ---------------------
 
                             HARBINGER CORPORATION
               (Exact name of issuer as specified in its charter)
 
<TABLE>
<S>                                               <C>
                    GEORGIA                                          58-1817306
            (State of Incorporation)                  (I.R.S. Employer Identification Number)
</TABLE>
 
                           1055 LENOX PARK BOULEVARD
                             ATLANTA, GEORGIA 30319
                                 (404) 467-3000
          (Address, including zip code and telephone number, including
 area code, of registrant's principal executive offices and principal place of
                                   business)
                             ---------------------
                              LOREN B. WIMPFHEIMER
                           DIRECTOR OF LEGAL AFFAIRS
                             HARBINGER CORPORATION
                           1055 LENOX PARK BOULEVARD
                             ATLANTA, GEORGIA 30319
                                 (404) 467-3000
                              (404) 841-3380 (FAX)
           (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)
                                   Copies to:
 
<TABLE>
<C>                                               <C>
              JOHN C. YATES, ESQ.                            ROBERT W. SMITH, JR., ESQ.
           LARRY W. SHACKELFORD, ESQ.                          PIPER & MARBURY L.L.P.
        MORRIS, MANNING & MARTIN, L.L.P.                        36 S. CHARLES STREET
         1600 ATLANTA FINANCIAL CENTER                       BALTIMORE, MARYLAND 21201
           3343 PEACHTREE ROAD, N.E.                               (410) 539-2530
             ATLANTA, GEORGIA 30326                             (410) 576-1700 (FAX)
                 (404) 233-7000
              (404) 365-9532 (FAX)
</TABLE>
 
                             ---------------------
    APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:  As soon as
practicable after the effective date of this Registration Statement.
    If the only securities being registered on this form are being offered
pursuant to dividend or interest reinvestment plans, please check the following
box.  [ ]
    If any of the securities being registered on this Form are offered on a
delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, other than securities offered only in connection with dividend or interest
reinvestment plans, please check the following box.  [ ]
    If this form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering.  [ ]
    If this form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering.  [ ]
    If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box.  [ ]
                             ---------------------
    THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL REGISTRANT SHALL
FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(A) OF
THE SECURITIES ACT OF 1933 OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SECTION 8(A), MAY
DETERMINE.
                The Index to Exhibits is located at Page II-11.
================================================================================
<PAGE>   2
 
     INFORMATION CONTAINED HEREIN IS SUBJECT TO COMPLETION OR AMENDMENT. A
     REGISTRATION STATEMENT RELATING TO THESE SECURITIES HAS BEEN FILED WITH THE
     SECURITIES AND EXCHANGE COMMISSION. THESE SECURITIES MAY NOT BE SOLD NOR
     MAY OFFERS TO BUY BE ACCEPTED PRIOR TO THE TIME THE REGISTRATION STATEMENT
     BECOMES EFFECTIVE. THIS PROSPECTUS SHALL NOT CONSTITUTE AN OFFER TO SELL OR
     THE SOLICITATION OF AN OFFER TO BUY NOR SHALL THERE BE ANY SALE OF THESE
     SECURITIES IN ANY STATE IN WHICH SUCH OFFER, SOLICITATION OR SALE WOULD BE
     UNLAWFUL PRIOR TO REGISTRATION OR QUALIFICATION UNDER THE SECURITIES LAWS
     OF ANY SUCH STATE.
 
                                                           SUBJECT TO COMPLETION
   
                                                                   JULY 28, 1997
    
 
                                2,900,000 SHARES
 
                                (LOGO) HARBINGER
 
                                  COMMON STOCK
                               ------------------
     Of the 2,900,000 shares of common stock ("Common Stock") offered hereby,
1,800,000 shares are being sold by Harbinger Corporation ("Harbinger" or the
"Company") and 1,100,000 shares are being sold by the selling shareholders named
herein (the "Selling Shareholders"). See "Principal and Selling Shareholders."
The Company will not receive any proceeds from the sale of shares of Common
Stock sold by the Selling Shareholders.
 
     The Company's Common Stock is traded on the Nasdaq National Market under
the symbol "HRBC." On July 15, 1997, the last reported sale price for the Common
Stock on the Nasdaq National Market was $36.625 per share. See "Price Range of
Common Stock."
 
     THE COMMON STOCK OFFERED HEREBY INVOLVES A HIGH DEGREE OF RISK. SEE "RISK
FACTORS" BEGINNING ON PAGE 6 HEREOF.
 
  THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
 EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION, NOR HAS THE SECURITIES
  AND EXCHANGE COMMISSION OR ANY STATE SECURITIES PASSED UPON THE ACCURACY OR
 ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL
                                    OFFENSE.
 
<TABLE>
<CAPTION>
=======================================================================================================================
                                               PRICE           UNDERWRITING          PROCEEDS            PROCEEDS
                                                TO             DISCOUNTS AND            TO              TO SELLING
                                              PUBLIC            COMMISSIONS         COMPANY(1)         SHAREHOLDERS
- -----------------------------------------------------------------------------------------------------------------------
<S>                                     <C>                 <C>                 <C>                 <C>
Per Share..............................          $                   $                   $                   $
- -----------------------------------------------------------------------------------------------------------------------
Total(2)...............................          $                   $                   $                   $
=======================================================================================================================
</TABLE>
 
(1) Before deducting estimated expenses of the offering estimated at $350,000.
    None of the expenses of the offering are being paid by the Selling
    Shareholders.
(2) The Company and the Selling Shareholders have granted the Underwriters a
    30-day option to purchase up to 435,000 additional shares of Common Stock
    solely to cover over-allotments, if any. To the extent that the option is
    exercised, the Underwriters will offer the additional shares at the Price to
    the Public shown above. If the option is exercised in full, the total Price
    to Public, Underwriting Discounts and Commissions, Proceeds to the Company
    and Proceeds to the Selling Shareholders will be $          , $          ,
    $          and $          , respectively. See "Underwriting."
                               ------------------
     The shares of Common Stock are offered by the Underwriters, subject to
prior sale, when, as and if delivered to and accepted by them and subject to the
right of the Underwriters to reject any order in whole or in part. It is
expected that delivery of the shares of Common Stock will be made at the offices
of Alex. Brown & Sons Incorporated, Baltimore, Maryland, on or about July   ,
1997.
 
ALEX. BROWN & SONS
        INCORPORATED
 
                 THE ROBINSON-HUMPHREY COMPANY, INC.
 
                                  ROBERTSON, STEPHENS & COMPANY
 
                                               INTERSTATE/JOHNSON LANE
                                                     CORPORATION
 
                 THE DATE OF THIS PROSPECTUS IS JULY   , 1997.
<PAGE>   3
 
                  [ACTIVE REVENUE GENERATING CUSTOMERS GRAPH]
 
IN CONNECTION WITH THIS OFFERING, THE UNDERWRITERS MAY OVER-ALLOT OR EFFECT
TRANSACTIONS WHICH STABILIZE, MAINTAIN OR OTHERWISE AFFECT THE PRICE OF THE
COMMON STOCK AT A LEVEL ABOVE THAT WHICH MIGHT OTHERWISE PREVAIL IN THE OPEN
MARKET. SPECIFICALLY, THE UNDERWRITERS MAY OVER-ALLOT IN CONNECTION WITH THE
OFFERING AND MAY BID FOR AND PURCHASE STOCK IN THE OPEN MARKET. FOR A
DESCRIPTION OF THESE ACTIVITIES, SEE "UNDERWRITING."
 
IN CONNECTION WITH THIS OFFERING, CERTAIN PERSONS PARTICIPATING IN THIS OFFERING
MAY ENGAGE IN PASSIVE MARKET MAKING TRANSACTIONS IN THE COMMON STOCK OF THE
COMPANY ON NASDAQ IN ACCORDANCE WITH RULE 103 UNDER REGULATION M. SEE
"UNDERWRITING."
 
                                        2
<PAGE>   4
 
                               PROSPECTUS SUMMARY
 
     The following summary is qualified in its entirety by the more detailed
information, including "Risk Factors" and consolidated financial statements and
notes thereto, appearing elsewhere or incorporated by reference in this
Prospectus.
 
                                  THE COMPANY
 
     Harbinger Corporation ("Harbinger" or the "Company") is a leading worldwide
provider of electronic commerce products and services to businesses and offers
comprehensive, customizable, standards-based electronic commerce solutions. The
Company develops, markets and supports software products and provides computer
communications network and consulting services which enable businesses to engage
in electronic commerce. These electronic commerce solutions are provided over
the Harbinger value-added network ("VAN") or the Company's Internet value-added
servers ("IVAS"), or directly over standard telephone lines, the Internet, or
private internal computer networks known as intranets. Harbinger offers software
products that operate on multiple computer platforms, secure and reliable
computer networks and secure Internet communications to facilitate the
transmission of business information and transactions, and value-added products
and services to enable businesses of all sizes to maximize the number and value
of their electronic trading relationships. As of March 31, 1997 the Company's
customers included leading U.S. and international corporations and government
agencies, including Northrop, Compaq Computer, Digital Equipment Corporation,
Hewlett-Packard, Westinghouse Electric, Baxter Healthcare, Johnson & Johnson,
Amoco, Chevron, Mobil, Pacific Gas & Electric, Southern California Edison, Bank
of America and Barnett Banks.
 
     The Company's products and services facilitate electronic commerce and
electronic data interchange ("EDI") by businesses and financial institutions by
providing the ability to electronically transmit and receive routine business
information and documents in a standard format. The Harbinger VAN and IVAS serve
as electronic communications links for computer systems by receiving, storing
and forwarding electronically transmitted business documents and data for re-
transmission in a form that can be received and interpreted by the computer of
another commercial business. The method of document exchange is user
configurable by trading partner and by document type (such as purchase order,
invoice, quote or bid request). Both the Harbinger VAN and IVAS provide
encryption and other document management and security methods to allow documents
to be exchanged securely and reliably. Harbinger facilitates the electronic link
to its computer communications network through its electronic commerce software
packages for use in a broad range of computing environments, including PC-based
solutions for DOS and Windows (3.x, 95 and NT Workstation), and client-server
solutions for Windows NT Server, UNIX, IBM AS/400 midrange and IBM MVS mainframe
platforms. The Company also provides professional services to assist businesses
in the installation, customization, operation and maintenance of their
electronic trading relationships.
 
     An important part of the Company's strategy is to enhance its suite of
electronic commerce products and services and to address new electronic trading
communities. The Company believes that the addition of new products and markets
from its recent acquisitions enhance Harbinger's ability to provide a
comprehensive range of solutions for trading partners to conduct business
electronically over the Harbinger VAN, IVAS, the Internet or private intranets.
The Company has made the following significant acquisitions since January 1,
1997:
 
     - SupplyTech -- On January 3, 1997, the Company completed a merger with
       SupplyTech, Inc. and its affiliate (collectively, "SupplyTech"), with
       operations in the U.S., United Kingdom, Italy, Australia and Mexico.
       SupplyTech, one of the largest providers of PC-based EDI software in the
       United States, provides its STX family of electronic commerce software
       products and services to, and allows the Company to expand into, trading
       communities in the automotive, retail, aerospace and heavy manufacturing
       markets.
                                        3
<PAGE>   5
 
     - HNS -- On January 1, 1997, the Company purchased the remaining equity
       interest in Harbinger NET Services, LLC ("HNS") and the related $3.0
       million Subordinated Convertible Debenture (the "Debenture") held by
       BellSouth Telecommunications, Inc. ("BellSouth"), thereby obtaining
       direct ownership of products designed to facilitate electronic commerce
       over the Internet. These products include IVAS, the Company's Internet
       value added server, TrustedLink Guardian, a security and encryption
       document management program, Harbinger Express, designed to permit EDI
       over the World Wide Web using a browser, and TrustedLink INP, a web site
       development tool. HNS was capitalized by the Company and certain other
       investors in 1995 to develop EDI products and services for the Internet,
       and prior to 1997 operated as a joint venture with BellSouth in which the
       Company held a 66.1% fully-diluted equity interest.
 
In connection with the SupplyTech transaction, the Company incurred in the first
quarter of 1997 a $7.1 million charge related to merger expenses and $4.8
million of integration costs. In connection with the HNS transactions, the
Company incurred in the first quarter 1997 a $2.4 million loss on the
extinguishment of the Debenture, a $2.7 million charge for in-process product
development, and $1.6 million of integration costs. See "Business -- Recent
Developments."
 
     The Company was incorporated in Georgia in 1988. The Company's principal
executive offices are located at 1055 Lenox Park Boulevard, Atlanta, Georgia
30319 and its telephone number is (404) 467-3000.
 
                      SECOND QUARTER RESULTS OF OPERATIONS
 
     On July 16, 1997, the Company announced its results of operations for the
quarter ended June 30, 1997. Revenue for the quarter ended June 30, 1997 was
$19.7 million compared to revenue of $14.8 million for the quarter ended June
30, 1996. Net income applicable to common shareholders for the quarter ended
June 30, 1997 was $2.2 million ($.11 per share) compared to net loss applicable
to common shareholders of $1.5 million (or($.08) per share) in the same period
in 1996. Operating income for the quarter ended June 30, 1997 was $3.7 million
compared to operating income of $252,000 for the same period in 1996. Adjusted
net income from the Company's core business (excluding the equity in loss of HNS
in 1996, net of related income taxes) was $2.2 million (or $.11 per share) for
the quarter ended June 30, 1997 compared to adjusted net income of $157,000 (or
$.01 per share) in the same period in 1996.
 
                                  THE OFFERING
 
Common Stock offered by the Company..........   1,800,000 shares
Common Stock offered by the Selling
Shareholders.................................   1,100,000 shares
Common Stock to be outstanding after this
offering(1)..................................   21,092,886 shares
Use of Proceeds..............................   Working capital and general
                                                corporate purposes, including
                                                acquisitions.
Nasdaq National Market symbol................   HRBC
- ---------------
 
(1) Excludes additional shares of Common Stock issuable upon the exercise of
    outstanding options and warrants, of which 1,175,823 shares are issuable
    under options and warrants exercisable at July 1, 1997.
 
     Except as otherwise noted, all information contained in this Prospectus (i)
assumes no exercise of the Underwriters' over-allotment option, (ii) reflects a
3-for-2 stock split paid in the form of a stock dividend on January 31, 1997 to
shareholders of record on January 17, 1997 and (iii) gives effect to the
restatement of the financial statements of the Company to reflect the
acquisition of SupplyTech, which was accounted for under the
pooling-of-interests method of accounting. This Prospectus (including the
documents incorporated by reference herein) contains forward-looking statements
that are based on the beliefs of, and estimates and assumptions made by and
information currently available to, the Company's management. Such statements
are subject to certain risks, uncertainties and assumptions. Actual results may
vary materially from those expected or anticipated in these forward-looking
statements as a result of certain factors, including those set forth under "Risk
Factors" and elsewhere in this Prospectus. See "Certain Forward Looking
Statements."
                                        4
<PAGE>   6
 
                         SUMMARY FINANCIAL INFORMATION
                     (IN THOUSANDS, EXCEPT PER SHARE DATA)
 
<TABLE>
<CAPTION>
                                                                                 THREE MONTHS ENDED
                                                    YEARS ENDED DECEMBER 31,         MARCH 31,
                                                  ----------------------------   ------------------
                                                   1994      1995       1996      1996       1997
                                                  -------   -------   --------   -------   --------
                                                                                    (UNAUDITED)
<S>                                               <C>       <C>       <C>        <C>       <C>
STATEMENT OF OPERATIONS DATA:
  Total revenues................................  $27,893   $37,830   $ 59,263   $11,504   $ 17,003
  Gross margin..................................   20,475    27,545     42,726     8,410     12,476
  Charge for purchased in-process product
    development and acquisition related
    charges.....................................    4,317     1,160      8,775     8,350     16,236
  Operating income (loss).......................   (2,667)      659     (5,736)   (7,876)   (13,326)
  Loss before income taxes and extraordinary
    item........................................   (2,921)     (539)   (12,921)   (8,965)   (13,280)
  Loss before extraordinary item................   (1,888)   (1,742)   (13,067)   (9,014)   (13,303)
  Extraordinary loss on debt extinguishment.....       --        --         --        --      2,419
                                                  -------   -------   --------   -------   --------
  Net loss......................................   (1,888)   (1,742)   (13,067)   (9,014)   (15,722)
  Preferred stock dividends.....................     (200)     (199)       (28)      (28)        --
                                                  -------   -------   --------   -------   --------
  Net loss applicable to common shareholders....  $(2,088)  $(1,941)  $(13,095)  $(9,042)  $(15,722)
                                                  =======   =======   ========   =======   ========
  Net loss per share of common stock:
    Loss before extraordinary item applicable to
       common shareholders......................  $ (0.16)  $ (0.13)  $  (0.71)  $ (0.51)  $  (0.70)
    Extraordinary loss on debt extinguishment...    --        --         --        --         (0.13)
                                                  -------   -------   --------   -------   --------
  Net loss per share of common stock............  $ (0.16)  $ (0.13)  $  (0.71)  $ (0.51)  $  (0.83)
                                                  =======   =======   ========   =======   ========
  Weighted average common and common equivalent
    shares outstanding..........................   12,693    15,007     18,465    17,903     18,930
                                                  =======   =======   ========   =======   ========
SUPPLEMENTAL DATA:
  Adjusted operating income(1)..................  $ 1,650   $ 1,819   $  3,039   $   474   $  2,910
                                                  =======   =======   ========   =======   ========
  Adjusted net income applicable to common
    shareholders(2).............................  $   652   $   762   $  1,715   $   274   $  1,803
                                                  =======   =======   ========   =======   ========
  Adjusted net income per common share(2).......  $  0.05   $  0.05   $   0.09   $  0.01   $   0.09
                                                  =======   =======   ========   =======   ========
</TABLE>
 
<TABLE>
<CAPTION>
                                                                     MARCH 31, 1997
                                                              ----------------------------
                                                                ACTUAL      AS ADJUSTED(3)
                                                              -----------   --------------
                                                              (UNAUDITED)    (UNAUDITED)
<S>                                                           <C>           <C>
BALANCE SHEET DATA:
  Working capital (deficit).................................    $(3,140)       $ 59,139
  Total assets..............................................     47,143         109,422
  Long-term obligations.....................................      1,305           1,305
  Shareholders' equity......................................     18,676          80,955
</TABLE>
 
- ---------------
 
(1) Excludes charges for purchased in-process product development and
    acquisition related charges.
(2) Excludes equity in loss of HNS, expected to recur, of $954,000, $7.0 million
    and $1.1 million for 1995, 1996, and the three months ended March 31, 1996,
    respectively, and $4.3 million, $1.2 million, $8.8 million, $8.4 million and
    $16.2 million in charges for 1994, 1995, 1996, and the three months ended
    March 31, 1996, and 1997, respectively, for purchased in-process product
    development and acquisition related charges. The three months ended March
    31, 1997 also excludes the extraordinary loss on debt extinguishment. All
    amounts are net of related income taxes. See "Acquisition-Related Charges;
    Loss in 1997 First Quarter and Expected Loss in Year Ended December 31,
    1997."
(3) Adjusted to reflect the sale by the Company of 1,800,000 shares of Common
    Stock at an assumed offering price of $36.625 per share, less estimated
    underwriting discounts and commissions and offering expenses of the Company,
    and the application of the net proceeds therefrom.
                                        5
<PAGE>   7
 
                                  RISK FACTORS
 
     In addition to the other information in this Prospectus, the following
factors should be considered in evaluating the Company and its business before
purchasing the Shares of Common Stock offered hereby.
 
     Integration of Recent Acquisitions.  The Company has completed a number of
acquisitions since January 1, 1996, including the acquisitions of SupplyTech and
the minority interests of HNS. SupplyTech and HNS have historically reported
significant operating losses. The Company's acquisitions present a number of
risks and challenges, including the historical operating losses of SupplyTech
and HNS, the integration of the SupplyTech software products into the Company's
current suite of products, the integration of the sales force of SupplyTech into
the Company's existing sales operations, the coordination of customer support
services, the integration of international operations of SupplyTech with the
Company's international affiliates, the development and commercialization of
HNS's Internet-related products and the integration of those products with the
Company's existing products, and the diversion of management's attention from
other business concerns. Several of the newly acquired products address the same
markets as, and may therefore be competitive with, existing Company products.
There can be no assurance that the Company can successfully assimilate its
operations and integrate its software products with these recently acquired
operations, software products and technologies, or that the Company will be
successful in repositioning its products on a timely basis to achieve market
acceptance. Any delay in such integration could have a material adverse effect
on the Company. See "Business -- Recent Developments."
 
     Factors Affecting Operating Results; Potential Fluctuations in Quarterly
Results.  The Company's quarterly operating results have in the past and may in
the future vary or decrease significantly depending on factors such as revenue
from software sales, the timing of new product and service announcements,
changes in pricing policies by the Company and its competitors, market
acceptance of new and enhanced versions of the Company's products, the size and
timing of significant orders, changes in operating expenses, changes in Company
strategy, personnel changes, government regulation, the introduction of
alternative technologies, the effect of acquisitions and general economic
factors. The Company has limited or no control over many of these factors. The
Company has experienced losses in the past, and at March 31, 1997, the Company
had an accumulated deficit of approximately $36.6 million. The Company operates
with virtually no software product order backlog because its software products
typically are shipped shortly after orders are received. As a result, revenues
in any quarter are substantially dependent on the quantity of purchases of
services requested and product orders received in that quarter. Quarterly
revenues also are difficult to forecast because the market for electronic
commerce and EDI software products is rapidly evolving and the Company's
revenues in any period may be significantly affected by the announcements and
product offerings of the Company's competitors as well as alternative
technologies. The Company's IVAS product is more complex and expensive compared
to the Company's other electronic commerce and Internet products introduced to
date, and will generally involve significant investment decisions by prospective
customers. Accordingly, the Company expects that in selling its IVAS product it
will encounter risks typical of companies that rely on large dollar purchase
decisions, including the reluctance of purchasers to commit to major investments
in new products and protracted sales cycles, both of which add to the difficulty
of predicting future revenues and may result in quarterly fluctuations. The
Company's expense levels are based, in part, on its expectations as to future
revenues. If revenue levels are below expectations, the Company may be unable or
unwilling to reduce expenses proportionately and operating results are likely to
be adversely affected. As a result, the Company believes that period-to-period
comparisons of its results of operations are not necessarily meaningful and
should not be relied upon as indications of future performance. Due to all of
the foregoing factors, it is likely that in some future quarter or quarters the
Company's operating results will be below the expectations of public market
analysts and investors. In such event, the price of the Company's Common Stock
will likely be adversely affected.
 
                                        6
<PAGE>   8
 
     The Company recognizes revenues for software license fees upon shipment,
net of estimated returns. Customers using the Company's PC products are
permitted to return products after delivery for a specified period, generally 60
days. The Company generally has experienced returns of approximately 20% of the
PC product license fees, and the Company records revenues after a deduction for
estimated returns. Any material increase in the Company's return experience
could have an adverse effect on its operating results. See "Acquisition-Related
Charges; Loss in 1997 First Quarter and Expected Loss in Year Ended December 31,
1997."
 
     Acquisition-Related Charges; Loss in 1997 First Quarter and Expected Loss
in Year Ended December 31, 1997.  In January 1997, the Company completed the
merger with SupplyTech, accounted for as a pooling of interests, and incurred a
$7.1 million first quarter 1997 charge related to merger related expenses.
Additionally, the Company incurred integration costs related to the merger of
$4.8 million during the first quarter of 1997. In January 1997, the Company
completed the purchase of the $3.0 million Subordinated Convertible Debenture of
HNS (the "Debenture") from BellSouth and the remaining equity in HNS from other
shareholders for an aggregate of approximately $9.8 million in consideration.
The Company incurred integration costs related to the HNS transaction of $1.6
million during the first quarter of 1997. Additionally, the Company incurred a
$2.4 million loss on extinguishment of the Debenture related to its purchase and
a $2.7 million charge for in-process product development related to the
acquisition of the minority interest of HNS in the first quarter of 1997. As a
result of these charges, the Company incurred a net loss for the first quarter
of 1997 and expects to incur a net loss for the year ending December 31, 1997.
The costs and expenses incurred in connection with the SupplyTech and HNS
integration activities included certain internal expense allocations which may
recur in other expense categories in the future and may result in an increase in
some expense categories as a percentage of total revenues. See "Integration of
Recent Acquisitions," "Risks of Potential Future Acquisitions" and "Business --
Recent Developments."
 
     Intense Competition.  The electronic commerce, EDI and network services and
products businesses are intensely competitive, and the Company has many
competitors with substantially greater financial, marketing, personnel and
technological resources than the Company. Other companies offer products and
services that may be considered by customers to be acceptable alternatives to
the Company's products and services. Certain companies also operate private
computer networks for transacting business with their trading partners. It is
expected that other companies may develop and implement similar
computer-to-computer networks, some of which may be "public" networks such as
the Company's and others may be "private," providing services only to a specific
group of trading partners, thereby reducing the Company's ability to increase
sales of its network services. In addition, several companies offer PC-based,
UNIX, midrange and mainframe and Internet computer software products which
compete with the Company's software products. Advanced operating systems and
applications software from Microsoft and other vendors also may offer electronic
commerce functions that limit the Company's ability to sell its software
products. The Company believes that the continuing acceptance of electronic
commerce and EDI will attract new competitors, including software applications
and operating systems companies that may bundle electronic commerce solutions
with their programs, and alternative technologies that may be more sophisticated
and cost effective than the Company's products and services. Competitive
companies may offer certain electronic commerce products or services, such as
communications software or network transactional services, at no charge or a
deeply discounted charge, in order to obtain the sale of other products or
services. Since the Company's agreements with its network subscribers are
terminable upon 30 days' notice, the Company does not have the contractual right
to prevent its customers from changing to a competing network. See "Dependence
on New Products; Industry Standards." Competitors that offer products and/or
services that compete with various of the Company's products and services
include, among others, Advantis Systems, Inc.; AT&T; Computer Associates
International, Inc.; EDS; General Electric Information Systems; Premenos
Technology Corp.; QuickResponse Services, Inc.; Sterling Commerce, Inc. and a
joint venture between British
 
                                        7
<PAGE>   9
 
Telecommunications Plc and MCI Communications Corporation; as well as the
internal programming staffs of various businesses engaging in electronic
commerce.
 
     Emergence of Electronic Commerce Over the Internet.  The Internet provides
a potential alternative means of providing electronic commerce to business
trading partners. The market for Internet software and services is both emerging
and highly competitive, ranging from small companies with limited resources to
large companies with substantially greater financial, technical and marketing
resources than the Company. In addition to the Company's Internet related
products and services, several existing competitors of the Company have
introduced their own Internet electronic commerce products and services.
Moreover, new competitors, which may include telephone companies and media
companies, are likely to increase the provision of business-to-business data
transmission services using the Internet. There is no assurance that the
Company's TrustedLink Guardian end user software and IVAS, which enable
electronic commerce over the Internet, will be accepted in the Internet market
or can be competitive with other products based on evolving technologies. If the
Internet becomes an accepted method of electronic commerce, the Company could
also lose network customers from its VAN which would reduce recurring revenue
from network services and have a material adverse effect on the Company.
 
     The use of the Company's Internet electronic commerce products and services
will depend in large part upon the continued development of the infrastructure
for providing Internet access and services. Use of the Internet for
business-to-business electronic commerce services raises numerous issues that
greatly impact the development of this market. These issues include reliability,
data security and data integrity, timely transmission, and pricing of products
and services. Because global commerce and online exchange of information on the
Internet is new and evolving, it is difficult to predict with any assurance
whether the Internet will prove to be a viable commercial marketplace. The
Internet has experienced, and is expected to continue to experience, substantial
growth in the number of users and the amount of traffic. There can be no
assurance that the Internet will continue to be able to support the demands
placed on it by this continued growth. In addition, the Internet could lose its
viability due to delays in the adoption of new standards and protocols to handle
increased levels of Internet activity, or due to increased governmental
regulation. There can be no assurance that the infrastructure or complementary
services necessary to make the Internet a viable commercial marketplace will be
developed, or, if developed, that the Internet will become a viable commercial
marketplace for products and services such as those offered by the Company. If
the necessary infrastructure or complementary services or facilities are not
developed, or if the Internet does not become a viable commercial marketplace,
the Company's business, operating results or financial condition will be
materially adversely affected. See "Dependence on New Products; Industry
Standards."
 
     Risks of Potential Future Acquisitions.  The Company's growth has been
significantly enhanced through acquisitions of other businesses, products and
licenses. Following this offering, the Company will have significant cash
resources, which may be used for acquisitions. There can be no assurance that in
the future the Company will be able to identify suitable acquisition candidates
available for sale at reasonable prices, consummate any acquisition or
successfully integrate any acquired business into the Company's operations.
Operational and software integration problems may arise if the Company
undertakes future acquisitions of complementary products, technologies or
businesses. Future acquisitions may also result in potentially dilutive
issuances of equity securities, the incurrence of additional debt, the write-off
of in-process product development and capitalized product costs, integration
costs, and the amortization of expenses related to goodwill and other intangible
assets, all of which could have a material adverse effect on the Company.
Acquisitions involve numerous additional risks, including difficulties in the
assimilation of the operations, products and personnel of the acquired company,
differing company cultures, the diversion of management's attention from other
business concerns, risks of entering markets in which the Company has little or
no direct prior experience, and the potential loss of key employees of the
acquired company. Customer satisfaction or performance problems at a single
acquired firm could have a material adverse impact on the reputation of the
Company as a whole. The Company
 
                                        8
<PAGE>   10
 
expects to finance any future acquisitions with the proceeds of this offering as
well as with possible debt financing, the issuance of equity securities (common
or preferred stock) or a combination of the foregoing. There can be no assurance
that the Company will be able to arrange adequate financing on acceptable terms.
See "Ability to Manage Growth."
 
     Dependence on New Products; Industry Standards.  The electronic commerce
industry is characterized by rapid technological change, frequent new product
and service introductions and evolving industry standards. The Company's future
success will depend in significant part on its ability to anticipate industry
standards, continue to apply advances in electronic commerce product and service
technologies, enhance existing products and services and introduce and acquire
new products and services on a timely basis to keep pace with technological
developments. There can be no assurance that the Company will be successful in
developing, acquiring or marketing new or enhanced products or services that
respond to technological change or evolving industry standards, that the Company
will not experience difficulties that could delay or prevent the successful
development, acquisition or marketing of such products or services or that its
new or enhanced products and services will adequately meet the requirements of
the marketplace and achieve market acceptance. In the past, the Company has
experienced delays in the commencement of commercial shipments of new products
and enhancements, resulting in delays or losses of product revenues. Such delays
or failure in the introduction of new or enhanced products or services, or the
failure of such products or services to achieve market acceptance, could have a
material adverse effect on the business, results of operations and financial
condition of the Company.
 
     Ability to Manage Growth.  The Company has recently experienced significant
growth in revenue, operations and personnel as it has made strategic
acquisitions, added subscribers to the Harbinger VAN and IVAS and increased the
number of licensees of its software products. This growth could continue to
place a significant strain on the Company's management and operations, including
its sales, marketing, customer support, research and development, finance and
administrative operations. Achieving and maintaining profitability during a
period of expansion will depend, among other things, on the Company's ability to
successfully expand its products, services and markets and to manage its
operations and acquisitions effectively. Difficulties in managing growth,
including difficulties in obtaining and retaining talented management and
product development personnel, especially following an acquisition, could have a
material adverse effect on the Company.
 
     Investment in International Subsidiaries; International Growth and
Operations.  The Company believes that its continued growth and profitability
will require expansion of its international operations through its international
subsidiaries, including NTEX Holding, B.V. ("NTEX") and INOVIS GmbH & Co.
("INOVIS") in Germany as well as the international operations of SupplyTech in
the United Kingdom, Italy, Australia and Mexico (the "International
Subsidiaries"). This expansion will require financial resources and significant
management attention, particularly by certain members of the management of the
Company. The Company's ability to successfully expand its business
internationally will also depend upon its ability to attract and retain both
talented and qualified managerial, technical and sales personnel and electronic
commerce services customers outside the United States and its ability to
continue to effectively manage its domestic operations while focusing on
international expansion. Certain of the International Subsidiaries have
experienced operating losses in their recent histories and some have experienced
significant operating losses in their recent histories. To the extent that the
International Subsidiaries are unable to penetrate international markets in a
timely and profitable manner, the Company's growth, if any, in international
sales will be limited, and the Company could be materially adversely affected.
Moreover, the Company's ability to successfully implement its international
strategy may require installation and operation of a value-added network and
implementation of its IVAS software in other countries, as well as additional
improvements to its infrastructure and management information systems, including
its international customer support systems. In addition, there can be no
assurance that the Company will be able to maintain or increase international
market demand for the Company's products or services. See "Integration of Recent
Acquisitions" and "Risks of Potential Future Acquisitions."
 
                                        9
<PAGE>   11
 
     International operations are subject to certain inherent risks, including
unexpected changes in regulatory requirements and tariffs, longer payment
cycles, increased difficulties in collecting accounts receivable and potentially
adverse tax consequences. To the extent international sales are denominated in
foreign currencies, gains and losses on the conversion to U.S. dollars of
revenues, operating expenses, accounts receivable and accounts payable arising
from international operations may contribute to fluctuations in the Company's
results of operations. The Company has not entered into any hedging or other
arrangements for the purpose of guarding against the risk of currency
fluctuation. In addition, sales in Europe and certain other parts of the world
typically are adversely affected in the third calendar quarter of each year
because many customers reduce their business activities in the summer months.
 
     Dependence on Key Management and Personnel; Ability to Attract and Retain
Qualified Personnel.  The Company's success is largely dependent upon its
executive officers and key sales and technical personnel, the loss of one or
more of whom could have a material adverse effect on the Company. The future
success of the Company will depend in large part upon its ability to attract and
retain talented and qualified personnel. In particular, the Company believes
that it will be important for the Company to hire experienced product
development and sales personnel. Competition in the recruitment of
highly-qualified personnel in the computer software and electronic commerce
industries is intense. The inability of the Company to locate and retain such
personnel may have a material adverse effect on the Company. No assurance can be
given that the Company can retain its key employees or that it can attract
qualified personnel in the future. The Company currently carries key-person life
insurance policies on the lives of Messrs. Howle and Leach, and expects to
purchase such insurance on the lives of Messrs. Davis, Travers and Annis. See
"Management."
 
     Dependence on Alliance Partners.  The Company has various agreements with
alliance partners for the distribution and marketing of certain software
products of the Company. These alliance partners pay the Company royalties
representing a percentage of fees generated from the sale of software licensed
from the Company. For the years ended December 31, 1995 and 1996, revenues from
one of these alliance partners were approximately $1.4 million and $5.7 million,
respectively, which equaled the contractual minimum royalty during those years.
There is no minimum royalty obligation after 1996, and the Company believes that
revenues from this alliance partner will substantially decline in 1997 as
compared to 1996. Further, based on recent amendments to the arrangement, the
Company believes that the average collection period related to cash flows
derived from royalty revenues earned from this alliance partner will lengthen
substantially.
 
     Risks of Product Development.  Software products as complex as those
offered by the Company may contain undetected errors or failures when first
introduced or when new versions are released. If software errors are discovered
after introduction, the Company could experience delays or lost revenues during
the period required to correct these errors. There can be no assurance that,
despite testing by the Company and by current and potential customers, errors
will not be found in new products or releases after commencement of commercial
shipments, resulting in loss of or delay in market acceptance, additional and
unexpected expenses to fund further product development or to add programming
personnel to complete a development project, and loss of revenue because of the
inability to sell the new product on a timely basis, any one or more of which
could have a material adverse effect on the Company. See "Business -- Products
and Services."
 
     Dependence on Data Centers.  The network service operations of the Company
are dependent upon the ability to protect computer equipment and the information
stored in the Company's data centers against damage that may be caused by fire,
power loss, telecommunication failures, unauthorized intrusion, computer viruses
and disabling devices and other similar events. Notwithstanding precautions the
Company has taken, there can be no assurance that a fire or other natural
disaster, including national, regional or local telecommunications outages,
would not result in a prolonged outage of the Company's network services. In the
event of a disaster, and depending on the nature of the disaster, it may take
from several hours to several days before the Company's off-site computer system
can become operational for all of the Company's customers, and use of the
alternative off-site computer would result in substantial additional cost to the
Company. In the event
 
                                       10
<PAGE>   12
 
that an outage of the Company's network extends for more than several hours, the
Company will experience a reduction in revenues by reason of such outage. In the
event that such outage extends for one or more days, the Company could
potentially lose many of its customers, which may have a material adverse effect
on the Company.
 
     Dependence upon Certain Licenses.  The Company relies on certain technology
that it licenses from third parties and other products that are integrated with
internally developed software and used in the Company's products to perform key
functions or to add important features. There can be no assurance that the
Company will be successful in negotiating third-party technology licenses on
suitable terms or that such licenses will not be terminated in the future.
Moreover, any delay or product problems experienced by such third party
suppliers could result in delays in introduction of the Company's products and
services until equivalent technology, if available, is identified, licensed and
integrated, which could have a material adverse effect on the Company's
business, operating results and financial condition.
 
     Limited Protection of Proprietary Technology; Risks of Infringement.  The
Company relies primarily on a combination of copyright, patent and trademark
laws, trade secrets, confidentiality procedures and contractual provisions to
protect its proprietary rights. The Company seeks to protect its software,
documentation and other written materials principally under trade secret and
copyright laws, which afford only limited protection. The Company presently has
one patent for an electronic document interchange test facility and a patent
application pending for an EDI communication system. Despite the Company's
efforts to protect its proprietary rights, unauthorized parties may attempt to
copy aspects of the Company's products or to obtain and use information that the
Company regards as proprietary. There can be no assurance that the Company's
means of protecting its proprietary rights will be adequate or that the
Company's competitors will not independently develop similar technology. In
distributing many of its products, the Company relies primarily on "shrink wrap"
licenses that are not signed by licensees and, therefore, may be unenforceable
under the laws of certain jurisdictions. In addition, the Company has licensed
it products to users and distributors in other countries, and the laws of some
foreign countries do not protect the Company's proprietary rights to as great an
extent as the laws of the United States. The Company does not believe that any
of its products infringe the proprietary rights of third parties. There can be
no assurance, however, that third parties will not claim infringement by the
Company with respect to current or future products, and the Company has agreed
to indemnify many of its customers against such claims. The Company expects that
software product developers will increasingly be subject to infringement claims
as the number of products and competitors in electronic commerce grows and the
functionality of products in different industry segments overlaps. Any such
claims, with or without merit, could be time-consuming, result in costly
litigation, cause product shipment delays or require the Company to enter into
royalty or licensing agreements and indemnify its customers against resulting
liability, if any. Such royalty or licensing agreements, if required, may not be
available on terms acceptable to the Company or at all, which could have a
material adverse effect on the Company.
 
     Government Regulatory and Industrial Policy Risks.  The Company's network
services are transmitted to its customers over dedicated and public telephone
lines. These lines are governed by Federal and state regulations establishing
the rates, terms and conditions for their use. Changes in the legislative and
regulatory environment relating to online services, EDI or the Internet access
industry, including regulatory or legislative changes which directly or
indirectly affect telecommunication costs, restrict content or increase the
likelihood of competition from regional telephone companies or others, could
have an adverse effect on the Company's business. The Telecommunications Act of
1996 ("Act") amended the federal telecommunications laws by lifting restrictions
on regional telephone companies and others competing with the Company and
imposed certain restrictions regarding obscene and indecent content communicated
to minors over the Internet or through interactive computer services. The Act
set in motion certain events that will lead to the elimination of restrictions
on regional telephone companies providing transport between defined
 
                                       11
<PAGE>   13
 
geographic boundaries associated with the provision of their own information
services. This will enable regional telephone companies to more readily compete
with the Company by packaging information service offerings with other services
and providing them on a wider geographic scale. While provisions of the Act
prohibiting the use of a telecommunications device or interactive computer
service to send or display indecent material to minors have been held by the
U.S. Supreme Court to be unconstitutional, there can be no assurance that future
legislative or regulatory efforts to limit use of the Internet in a manner
harmful to the Company will not be successful. The Clinton administration has
announced an initiative to establish a framework for global electronic commerce.
Also, some countries such as Germany have adopted laws regulating aspects of the
Internet, and there are a number of bills currently being considered in the
United States at the federal and state levels involving encryption and digital
signatures, all of which may impact the Company. The Company cannot predict the
impact, if any, that the Act and future court opinions, legislation, regulations
or regulatory changes in the United States or other countries may have on its
business. Management believes that the Company is in compliance with all
material applicable regulations.
 
     Anti-Takeover Provisions.  The Board of Directors has authority to issue up
to 20,000,000 shares of preferred stock and to fix the rights, preferences,
privileges and restrictions, including voting rights, of the preferred stock
without further vote or action by the Company's shareholders. The rights of the
holders of Common Stock will be subject to, and may be adversely affected by,
the rights of the holders of any preferred stock that may be issued in the
future. While the Company has no present intention to issue additional shares of
preferred stock, such issuance, while providing desired flexibility in
connection with possible acquisitions and other corporate purposes, could have
the effect of making it more difficult for a third party to acquire a majority
of the outstanding voting stock of the Company. In addition, the Company's
Amended and Restated Articles of Incorporation and Bylaws contain provisions
that may discourage proposals or bids to acquire the Company. This could limit
the price that certain investors might be willing to pay in the future for
shares of Common Stock. The Company's Amended and Restated Articles of
Incorporation provide for a classified Board of Directors with three-year,
staggered terms for its members. The classification of the Board of Directors
could have the effect of making it more difficult for a third party to acquire
control of the Company.
 
                                       12
<PAGE>   14
 
                                USE OF PROCEEDS
 
     The net proceeds to the Company from the sale of the 1,800,000 shares of
Common Stock offered by it hereby are estimated to be $62.3 million ($71.7
million if the Underwriters' over-allotment option is exercised in full) after
deducting estimated underwriting discounts and commissions and offering expenses
and assuming a public offering price of $36.625 per share (the last reported
sale price of the Common Stock on the Nasdaq National Market on July 15, 1997).
The Company will not receive any of the proceeds from the sale of the shares by
the Selling Shareholders. The Company intends to use such proceeds for working
capital and general corporate purposes, which may include acquisitions and
possible facilities expansion. From time to time, the Company evaluates various
acquisition candidates. As of the date hereof, the Company has no definitive
agreement to acquire any business whose operations are significant to the
Company. Pending such use, the Company currently intends to invest the net
proceeds of this offering in short term, investment grade debt securities and
other marketable securities.
 
                          PRICE RANGE OF COMMON STOCK
 
     The Company's Common Stock is listed on the Nasdaq National Market under
the symbol "HRBC." The following table sets forth the range of high and low
closing sale prices for the Company's Common Stock on the Nasdaq National Market
during the periods indicated commencing August 22, 1995, the date of the
Company's initial public offering. The prices reported reflect the Company's
3-for-2 stock split paid in the form of a stock dividend on January 31, 1997 to
shareholders of record as of January 17, 1997.
 
<TABLE>
<CAPTION>
                                                              HIGH    LOW
                                                              ----    ---
<S>                                                           <C>     <C>
Year Ended December 31, 1995:
  Quarter Ended:
     September 30, 1995.....................................  $11 5/8  $ 8 5/8
     December 31, 1995......................................   19 5/8    8 1/8
Year Ended December 31, 1996:
  Quarter Ended:
     March 31, 1996.........................................   15 5/8   10 1/8
     June 30, 1996..........................................   18 1/2   10
     September 30, 1996.....................................   18 5/8   13 1/4
     December 31, 1996......................................   19 1/4   16 5/8
Year Ended December 31, 1997:
  Quarter Ended:
     March 31, 1997.........................................   29       17 5/8
     June 30, 1997..........................................   31 1/2   19 1/4
     September 30, 1997 (through July 15, 1997).............   36 5/8   27 1/4
</TABLE>
 
     On July 15, 1997, the closing sale price of the Common Stock on the Nasdaq
National Market was $36.625 per share.
 
                                DIVIDEND POLICY
 
     The Company has never declared or paid any cash dividends on its Common
Stock. The Company currently anticipates that it will retain all future earnings
for use in its business and does not anticipate paying cash dividends in the
foreseeable future. In addition, the Company's loan agreements contain covenants
which restrict the Company's ability to pay cash dividends.
 
                                       13
<PAGE>   15
 
                                 CAPITALIZATION
 
     The following table sets forth the capitalization of the Company as of
March 31, 1997, and the capitalization as adjusted to give effect to the
completion of this offering and the receipt by the Company of the estimated net
proceeds therefrom, assuming a public offering price of $36.625 per share. See
"Use of Proceeds" and "Description of Capital Stock." This table should be read
in conjunction with the Company's historical consolidated financial statements
and the other information included and incorporated by reference in this
Prospectus.
 
<TABLE>
<CAPTION>
                                                                   MARCH 31, 1997
                                                              -------------------------
                                                              HISTORICAL    AS ADJUSTED
                                                              ----------    -----------
                                                                   (IN THOUSANDS)
<S>                                                           <C>           <C>
Long-term debt, excluding current portion...................   $  1,305      $  1,305
                                                               --------      --------
Redeemable preferred stock:
  Zero Coupon; 4,000,000 shares issued and outstanding......         --            --
Shareholders' equity:
  Preferred stock, 20,000,000 shares authorized, none issued
     or outstanding.........................................         --            --
  Common Stock, $.0001 par value per share; 100,000,000
     shares authorized; 19,007,855 shares issued and
     outstanding; 20,807,855 issued and outstanding, as
     adjusted (1)...........................................          2             2
  Additional paid-in capital................................     55,320       117,599
  Accumulated deficit.......................................    (36,646)      (36,646)
                                                               --------      --------
          Total shareholders' equity........................   $ 18,676      $ 80,955
                                                               --------      --------
            Total capitalization............................   $ 19,981      $ 82,260
                                                               ========      ========
</TABLE>
 
- ---------------
 
(1) Excludes approximately 3,373,385 additional shares of Common Stock issuable
    upon the exercise of outstanding options and warrants, 1,175,823 of which
    shares are issuable under options and warrants exercisable at July 1, 1997.
 
                                       14
<PAGE>   16
 
                            SELECTED FINANCIAL DATA
 
     The following selected financial data should be read in conjunction with
the consolidated financial statements and notes thereto of the Company and
"Management's Discussion and Analysis of Financial Condition and Results of
Operations" incorporated by reference in this Prospectus. See "Incorporation of
Certain Information by Reference." The consolidated financial data for the three
months ended March 31, 1996 and 1997 have been derived from the unaudited
consolidated financial statements of the Company, but include all adjustments
(consisting only of normal recurring adjustments) which the Company considers
necessary for a fair presentation of the results of operations for the periods
presented. The results of operations for the three month period ended March 31,
1997 may not be indicative of the operating results that may be expected for the
Company's fiscal year ended December 31, 1997.
 
<TABLE>
<CAPTION>
                                                                                                               THREE MONTHS
                                                                                                                  ENDED
                                                                                                                MARCH 31,
                                                                     YEAR ENDED DECEMBER 31,                   (UNAUDITED)
                                                         ------------------------------------------------   ------------------
                                                          1992      1993      1994      1995       1996      1996       1997
                                                         -------   -------   -------   -------   --------   -------   --------
                                                                         (IN THOUSANDS, EXCEPT PER SHARE DATA)
<S>                                                      <C>       <C>       <C>       <C>       <C>        <C>       <C>
STATEMENT OF OPERATIONS DATA:
  Revenues:
    Services...........................................  $ 8,721   $12,502   $17,481   $24,494   $ 37,822   $ 7,497   $ 12,117
    Software...........................................    8,061    10,098    10,412    13,336     21,441     4,007      4,886
                                                         -------   -------   -------   -------   --------   -------   --------
        Total revenues.................................   16,782    22,600    27,893    37,830     59,263    11,504     17,003
                                                         -------   -------   -------   -------   --------   -------   --------
  Direct costs:
    Services...........................................    3,833     5,179     6,321     8,334     13,625     2,419      3,883
    Software...........................................      609       837     1,097     1,951      2,912       675        694
                                                         -------   -------   -------   -------   --------   -------   --------
        Total direct costs.............................    4,442     6,016     7,418    10,285     16,537     3,094      4,527
                                                         -------   -------   -------   -------   --------   -------   --------
  Gross margin.........................................   12,340    16,584    20,475    27,545     42,726     8,410     12,476
                                                         -------   -------   -------   -------   --------   -------   --------
  Operating costs:
    Selling and marketing..............................    5,008     6,802     7,995     9,791     15,057     3,056      3,482
    General and administrative.........................    4,418     5,302     5,884     8,647     12,664     2,752      3,356
    Depreciation and amortization......................      656       841     1,046     1,361      2,966       491        985
    Product development................................    1,893     2,827     3,900     5,927      9,000     1,637      1,743
    Charge for purchased in-process product development
      and acquisition related charges..................       --        --     4,317     1,160      8,775     8,350     16,236
                                                         -------   -------   -------   -------   --------   -------   --------
        Total operating costs..........................   11,975    15,772    23,142    26,886     48,462    16,286     25,802
                                                         -------   -------   -------   -------   --------   -------   --------
  Operating income (loss)..............................      365       812    (2,667)      659     (5,736)   (7,876)   (13,326)
  Reorganization costs.................................      194        --        --        --         --        --         --
  Interest expense (income), net.......................      128         4        27       (68)        (7)      (90)       (64)
  Equity in losses of joint ventures...................       --        41       227     1,266      7,192     1,179         18
                                                         -------   -------   -------   -------   --------   -------   --------
        Income (loss) before income tax expense
          (benefit) and extraordinary item.............       43       767    (2,921)     (539)   (12,921)   (8,965)   (13,280)
  Income tax expense (benefit).........................       65    (2,631)   (1,033)    1,203        146        49         23
                                                         -------   -------   -------   -------   --------   -------   --------
        Income (loss) before extraordinary item........      (22)    3,398    (1,888)   (1,742)   (13,067)   (9,014)   (13,303)
  Extraordinary loss on debt extinguishment............       --        --        --        --         --        --      2,419
                                                         -------   -------   -------   -------   --------   -------   --------
        Net income (loss)..............................      (22)    3,398    (1,888)   (1,742)   (13,067)   (9,014)   (15,722)
  Preferred stock dividends............................     (200)     (327)     (200)     (199)       (28)      (28)        --
                                                         -------   -------   -------   -------   --------   -------   --------
  Net income (loss) applicable to common shareholders..  $  (222)  $ 3,071   $(2,088)  $(1,941)  $(13,095)  $(9,042)  $(15,722)
                                                         =======   =======   =======   =======   ========   =======   ========
  Net income (loss) per share of common stock:
    Income (loss) before extraordinary item applicable
      to common shareholders...........................  $ (0.02)  $  0.25   $ (0.16)  $ (0.13)  $  (0.71)  $ (0.51)  $  (0.70)
    Extraordinary loss on debt extinguishment..........    --        --        --        --         --        --         (0.13)
                                                         -------   -------   -------   -------   --------   -------   --------
  Net income (loss) per share applicable to common
    shareholders.......................................  $ (0.02)  $  0.25   $ (0.16)  $ (0.13)  $  (0.71)  $ (0.51)  $  (0.83)
                                                         =======   =======   =======   =======   ========   =======   ========
  Weighted average common and common equivalent shares
    outstanding........................................   10,867    12,515    12,693    15,007     18,465    17,903     18,930
                                                         =======   =======   =======   =======   ========   =======   ========
Pro forma net loss data(1):
  Pro forma net loss applicable to common
    shareholders.......................................                                $(1,425)  $(13,095)
                                                                                       =======   ========
  Pro forma net loss per common share..................                                $ (0.10)  $  (0.71)
                                                                                       =======   ========
  Weighted average common and common equivalent shares
    outstanding........................................                                 15,007     18,465
                                                                                       =======   ========
 
SUPPLEMENTAL DATA:
  Adjusted operating income(2).........................  $   365   $   812   $ 1,650   $ 1,819   $  3,039   $   474   $  2,910
                                                         =======   =======   =======   =======   ========   =======   ========
  Adjusted net income (loss) applicable to common
    shareholders(3)....................................  $  (222)  $ 3,071   $   652   $   762   $  1,715   $   274   $  1,803
                                                         =======   =======   =======   =======   ========   =======   ========
  Adjusted net income (loss) per common share(3).......  $ (0.02)  $  0.25   $  0.05   $  0.05   $   0.09   $  0.01   $   0.09
                                                         =======   =======   =======   =======   ========   =======   ========
</TABLE>
 
                                       15
<PAGE>   17
 
<TABLE>
<CAPTION>
                                                                              DECEMBER 31,
                                                            ------------------------------------------------    MARCH 31,
                                                             1992      1993      1994      1995       1996        1997
                                                            -------   -------   -------   -------   --------   -----------
                                                                                                               (UNAUDITED)
<S>                                                         <C>       <C>       <C>       <C>       <C>        <C>
BALANCE SHEET DATA:
  Working capital (deficit)...............................  $   590   $ 3,964   $ 2,838   $11,564   $  3,190     $(3,140)
  Total assets............................................    9,038    16,923    21,347    46,404     48,793      47,143
  Long-term obligations, redeemable preferred stock, and
    puttable common stock.................................    7,331     5,146     3,016     6,347      1,449       1,305
  Shareholders' equity....................................   (2,973)    5,649     6,734    27,509     24,842      18,676
</TABLE>
 
- ---------------
 
(1) The pro forma net loss reflects the income tax expense that would have been
    reported if SupplyTech, Inc. (an S corporation for income tax reporting
    purposes) and SupplyTech International, LLC (a limited liability corporation
    for income tax reporting purposes) had been C corporations during these
    periods.
(2) Excludes purchased in-process product development and acquisition related
    charges. See "Acquisition - Related Charges; Loss in 1997 First Quarter and
    Expected Loss in Year Ended December 31, 1997."
(3) Excludes equity in loss of HNS, expected to recur, of $954,000, $7.0
    million, and $1.1 million for 1995, 1996, and the three months ended March
    31, 1996, respectively, and $4.3 million, $1.2 million, $8.8 million, $8.4
    million and $16.2 million in charges for 1994, 1995, 1996, and the three
    months ended March 31, 1996, and 1997, respectively, for purchased
    in-process product development and acquisition related charges. The three
    months ended March 31, 1997 also excludes the extraordinary loss on debt
    extinguishment. All amounts are net of related income taxes. See
    "Acquisition - Related Charges; Loss in 1997 First Quarter and Expected Loss
    in Year Ended December 31, 1997."
 
                                       16
<PAGE>   18
 
                                    BUSINESS
 
     The Company is a leading worldwide provider of electronic commerce products
and services to businesses and offers comprehensive, customizable,
standards-based electronic commerce solutions. Harbinger develops, markets and
supports software products and provides computer communications network and
consulting services which enable businesses to engage in electronic commerce.
These electronic commerce solutions are provided over the Harbinger VAN or the
Company's IVAS, or directly over standard telephone lines, the Internet, or
private internal computer networks known as Intranets. Harbinger offers software
products that operate on multiple computer platforms, secure and reliable
computer networks to facilitate the transmission of business information and
transactions, and value-added products and services to enable businesses of all
sizes to maximize the number and value of their electronic trading
relationships. As of March 31, 1997, the Company's customers included leading
U.S. and international corporations and government agencies, including Northrop,
Compaq Computer, Digital Equipment Corporation, Hewlett-Packard, Westinghouse
Electric, Baxter Healthcare, Johnson & Johnson, Amoco, Chevron, Mobil, Pacific
Gas & Electric, Southern California Edison, Bank of America and Barnett Banks.
 
     The Company's products and services facilitate electronic commerce and EDI
by businesses and financial institutions by providing the ability to
electronically transmit and receive routine business information and documents
in a standard format. The Harbinger VAN and IVAS serve as electronic
communications links for computer systems by receiving, storing and forwarding
electronically transmitted business documents and data for re-transmission in a
form that can be received and interpreted by the computer of another commercial
business. The method of document exchange is user configurable by trading
partner and by document type (such as purchase order, invoice, quote and similar
business documents). Both the Harbinger VAN and IVAS provide encryption and
other document management and security methods to allow documents to be
exchanged securely and reliably. Harbinger facilitates the electronic link to
its computer communications network through its electronic commerce software
packages for use in a broad range of computing environments, including PC-based
solutions for DOS and Windows (3.x, 95 and NT Workstation), and client-server
solutions for Windows NT Server, UNIX, IBM AS/400 midrange and IBM MVS mainframe
platforms. The Company also provides professional services to assist businesses
in the installation and customization, operation and maintenance of their
electronic trading relationships.
 
RECENT DEVELOPMENTS
 
     In January 1997, the Company consummated the merger with SupplyTech.
SupplyTech provides electronic commerce software products and services under the
"STX" brand. The acquisition allowed the Company to expand into trading
communities in the automotive, retail, aerospace and heavy manufacturing
markets. In addition to being one of the largest providers of PC-based EDI
translation software in the United States, SupplyTech also has operations in the
United Kingdom, Italy, Australia and Mexico. The merger was accounted for as a
pooling-of-interests. Management of the Company anticipates that this merger
will broaden the Company's markets and customer base, add complementary products
and technologies, strengthen its ability to offer electronic commerce software
and services to its customers and diversify its revenue base. SupplyTech now
operates under the name Harbinger SupplyTech.
 
     In January 1997, the Company purchased the remaining equity interest in HNS
and the Debenture, thereby obtaining direct ownership of products designed to
facilitate electronic commerce over the Internet. These products include IVAS,
TrustedLink Guardian, a security and encryption document management program,
Harbinger Express, designed to permit EDI over the World Wide Web using a
browser, and TrustedLink INP, a web site development tool. HNS was capitalized
by the Company in 1995 to develop EDI products and services for the Internet,
and prior to 1997 operated as a joint venture with BellSouth in which the
Company held a 66.1% fully-diluted equity interest.
 
                                       17
<PAGE>   19
 
ELECTRONIC COMMERCE AND EDI
 
     Electronic commerce involves the automation of business transactions
through the use of telecommunications and computers to exchange and
electronically process commercial information and transactional documents.
Electronic commerce typically involves the use of a third-party or private
value-added computer network to perform EDI, electronic funds transfer,
electronic forms, and bulletin board and electronic catalog services. EDI is a
cornerstone of electronic commerce and has historically been the source of the
majority of the Company's revenue. The advantages of EDI include one-time data
entry, reduced clerical workload and the elimination of paper records, rapid,
accurate and secure exchange of business data, and reduced operating and
inventory carrying costs. EDI facilitates uniform communications with different
trading partners in different industries, including customers, suppliers, common
carriers, and banks or other financial institutions.
 
     EDI Transaction Flow.  In a typical EDI transaction, a trading partner (the
"sending partner") first creates with its computer, either manually or
electronically, the business data used for the completion of a particular set of
documents, described by EDI standards as a transaction set. Transaction sets
include requests for quotes, quotes, purchase orders, invoices, shipping
notices, and other related documents and messages. Second, a translation
software program on the sending partner's computer converts the document or
transaction set into a standard EDI format. The most frequently used such
formats are ANSI X.12 in the United States and EDIFACT in the rest of the world.
Third, this information is electronically transmitted through telecommunications
links from the sending partner's computer to a central computer system that
serves as a value-added network shared by many trading partners. Value-added
networks receive documents for subsequent delivery to the intended trading
partner (the "receiving partner"), and connect many types of computer hardware
and communications devices, convert multiple transaction sets from one industry
standard to another, and maintain security by reducing the possibility of one
trading partner obtaining unauthorized access to another computer.
 
     Trading Communities.  Groups of companies that regularly trade with each
other generate significant repetitive business transactions. These existing
trading communities are natural prospects for implementation of EDI. The
expansion of EDI has been possible through the establishment of repetitive
transactions using the two major standards noted above. In addition, there are
now subsets of these standards used in specific industries such as automotive,
banking, chemical, financial, grocery, healthcare, petroleum, retail and
utilities. The adoption of EDI as an accepted means of transmitting business
documents and data has also occurred, in part, because many trade organizations
or groups and many large companies within a trading community increasingly
recommend or require their member organizations or trading partners to adopt and
use EDI as the primary method of communicating business documents.
 
     Hubs and Spokes.  Large companies within a trading community often are
described as "hubs" and their trading partners as "spokes." A hub company and
its trading partners communicate through electronic networks. These can be third
party networks and, for a few larger businesses, private networks owned and
operated by the hub company. Hub companies often initially justify EDI programs
with direct cost savings to reduce the administrative handling costs and to
eliminate data entry errors of the documents that they send and receive from
trading partners. Advanced EDI implementations by a hub company may be more
strategic in nature, being utilized as enabling technologies for business
processes such as supply chain management and just-in-time manufacturing, and
efficient consumer response and vendor managed inventory in retailing. For these
reasons, a hub company often adopts as a stated business objective that all of
its trading partners use EDI as the principal means of communicating business
documents. Spoke companies, in turn, often expand the electronic commerce
community by also requesting or requiring their other trading partners to
communicate through EDI. This expanding number of trading partners adopting EDI
results in the establishment of distinct trading communities comprising
potential software customers and network subscribers for EDI services.
 
                                       18
<PAGE>   20
 
     According to International Data Corporation, the worldwide market for
electronic commerce was an estimated $1.5 billion in revenues in 1995 and is
estimated to increase to almost $4.0 billion by 2000, an average annual growth
rate of approximately 21%. Furthermore, it is estimated by The EDI Group, Ltd.
that of the 3 million U.S. companies with five or more employees, approximately
120,000 have elected to date to make use of EDI. Although many of these current
users of EDI are members of defined trading communities, the Company believes
that the majority of the members of these trading communities use electronic
commerce solutions to communicate with a very small percentage of their trading
partners. Acceptance of electronic commerce and expansion within trading
communities will depend on various factors, such as the extent of automation in
the industry, the degree to which hub companies require electronic trading from
their trading partners, the level of computer sophistication of businesses in
the trading community, the frequency of transactions among trading partners in
the community and the economic benefits derived from the trading community by
implementing electronic trading which historically have accrued principally to
the larger members of the community. To date, EDI has minimal penetration in
small companies because (i) current EDI solutions have not provided significant
added value, and (ii) EDI is not pervasive among the average small company's
trading partners.
 
THE HARBINGER SOLUTION
 
     The Harbinger solution to addressing electronic commerce is based on the
following five components which are designed to build trading partner
relationships and generate recurring revenue. The Company believes these
components differentiate it from its competitors in the market.
 
     - Comprehensive Product Offering.  The Company offers a range of electronic
       commerce software solutions for trading communities, including a suite of
       fully scaleable EDI translation software, EDI modules for supply chain
       management, its VAN and IVAS solutions, electronic catalogs, and web site
       creation and management software for small businesses.
 
     - Mass Deployment Services.  The Company provides mass deployment services
       to trading community leaders to permit them to plan, manage and deploy
       EDI and electronic commerce solutions to their trading partners through
       the use of trading partner conferences and direct marketing services.
 
     - Trading Relationship Management Services.  The Company provides a range
       of trading relationship management services, including installation
       assistance, trading partner certification and rules, and services such as
       customization, training and consulting.
 
     - Vertical Market Expertise.  The Company has developed vertical market
       expertise in selected industries such as aerospace, automotive,
       electronics, financial services, food and beverage, government,
       healthcare, heavy manufacturing, petroleum/chemicals, retail and
       utilities.
 
     - Flexible, Secure Value Added Architecture.  The Company has developed a
       combined network architecture utilizing the VAN and the IVAS which
       permits secure and reliable network and secure Internet communications to
       facilitate the transmission of business information and transactions.
 
                                       19
<PAGE>   21
 
PRODUCTS AND SERVICES
 
     The Company offers a comprehensive range of electronic commerce products
and services for entire trading communities. These Company offerings are divided
into three categories, providing electronic commerce solutions for large
companies, solutions designed for small and mid-sized companies, and services
for entire trading communities engaged in electronic commerce. The following
chart summarizes the functions and platforms of the Company's principal
electronic commerce software products and includes a description of the services
available to software customers and network subscribers:
 
<TABLE>
<CAPTION>
                                                                                               COMPUTER
        PRODUCT NAME                                 FUNCTION                                  PLATFORM
- ----------------------------  -------------------------------------------------------  ------------------------
<S>                           <C>                                                      <C>
SOLUTIONS FOR LARGE BUSINESSES
  TrustedLink Enterprise      EDI translation communications, document management,      UNIX, Windows NT, IBM
                              plus import/export of data from software applications        MVS, IBM AS/400
  STX                         EDI translation communications, document management,       IBM MVS, IBM AS/400,
                              plus import/export of data from software applications            DOS/VSE
  TrustedLink Guardian        Data encryption and communications software for            Windows 95/NT, UNIX
                              transmitting EDI documents over the Internet
  Internet Value Added        Intermediation, archival, standards compliance and           Unix/Windows NT
  Server (IVAS)               trusted third party services via the Internet
  EDI*Benchmark and           EDI translation software                                     IBM MVS, DOS/VSE
  EDI*Central
 
SOLUTIONS FOR SMALL AND MID-SIZE BUSINESSES
  TrustedLink Commerce        EDI translation communications, document management and   DOS, Windows, Windows
                              forms creation, plus import/export of data from                   95/NT
                              software applications
  STX                         EDI translation communications, document management and        DOS, Windows
                              forms creation, plus import/export of data from
                              software applications
  Harbinger Express           Software allowing users with only a web browser to send   Web browser on Windows
                              and receive EDI documents
  STSECURITY                  Software for encrypting EDI documents for transmission           Windows
                              over the Internet
  TrustedLink Banker          Small business cash management, electronic funds               DOS, Windows
                              transfer, wire transfers, direct deposits and debits
  TrustedLink Distributor     EDI communications, document management and forms                Windows
  for Petroleum               creation for petroleum manufacturers and distributors
  Third Party Ticket System   Translation of EDI documents to facilitate ownership             Windows
                              tracking for petroleum companies
  ESRS                        Solution for complying with retail vendor shipping             DOS, Windows
                              requirements
  STBAR                       Bar code labeling software                                     DOS, Windows
  Pronto                      Software for profiling government suppliers to submit          DOS, Windows
                              response to bids
  TrustedLink INP             Software permitting rapid development of a World Wide            Windows
                              Web site for promoting and selling products and
                              services via the Internet
</TABLE>
 
                                       20
<PAGE>   22
 
<TABLE>
<CAPTION>
             SERVICES                                       DESCRIPTION
- ----------------------------------  ------------------------------------------------------------
<S>                                 <C>
Value-Added Network Services        Fault tolerant, store and forward, retrieval services,
                                    protocol conversion, electronic mail box
Internet Value-Added Server (IVAS)  Intermediation, archival, standards compliance monitoring,
Services                            and trusted third party services via the Internet
Harbinger Net Access                Internet access
EDI to Fax Services                 Translation of EDI documents to fax format
Trading Partner Certification       Information seminars, support materials, testing and
                                    confirmation of EDI communications with trading partners
Trading Partner Implementation      Creation of trading partner packs for users to exchange
Service                             documents with other trading partners
Consulting and Programming          Development of computer programs needed to integrate EDI
Services                            with customers other software applications
Electronic Catalogs                 Comprehensive electronic catalog solutions for supply chain
                                    management and maintenance, repair and operating initiatives
Customer Support                    Telephone hotline, support documentation, network
                                    transmission support, electronic software updates
Bid Filtering and Profiling         Service which matches government bids with product suppliers
  Service
FAX-2-EDI                           Service which converts Faxes to EDI format for submitting to
                                    government agencies
</TABLE>
 
  Solutions for Large Businesses
 
     TrustedLink Enterprise for High-End Computing Platforms.  The TrustedLink
Enterprise product permits fast receipt and transmission of EDI documents and
supports a comprehensive range of EDI standards across all major computing
platforms. The Company offers this product for MVS mainframe, UNIX and Windows
NT Server. The product facilitates the creation and control of business
documents, such as order forms and invoices, in complex client/server computing
environments, and provides data linking and messaging functions which act as a
gateway to update a trading partner's accounting system. The product also offers
mapping, translation, communication and trading partner management tools and
utilize standard EDI formats.
 
     TrustedLink Guardian.  TrustedLink Guardian is an open, standards-based
solution for enabling secure EDI over the Internet. TrustedLink Guardian is
available for both UNIX and Windows systems. It consists of messaging, security,
authentication and management modules which automatically integrate with the
Company's existing EDI translators.
 
     Internet Value-Added Server (IVAS).  Similar to the Harbinger VAN, the
Company's IVAS offers many of the same value-added services over the Internet.
The IVAS provides intermediation, archiving, standards compliance monitoring and
third-party services via the Internet. In conjunction with the Company's VAN,
the IVAS permits participants in a trading community to select the desired
communications transport mechanism for individual documents of a typical EDI
transaction. IVAS is also offered as a product for license by end users. IVAS/P
is tailored to enable public operators to offer electronic commerce services in
their local market, while IVAS/E is intended for large enterprises directly
operating a server platform to link members of the enterprise's trading
community typically through a private intranet.
 
     Mass Deployment Services.  Harbinger offers mass deployment services to
trade organizations or hub companies within selected industries to establish and
promote the growth of trading communities. Initially, the Company develops
marketing and technical competence within an industry by learning the trading
customs and practices of their trading partners. The Company then defines the
software and computer system requirements for the promotion of electronic
commerce in the trading community. These definitions are used to develop
standard and customized software products to meet the needs of trading partners
within their own markets. These products are complemented by an array of
services to facilitate the adoption and implementation of EDI and other
electronic commerce services throughout that industry.
 
     Web Application Services.  Harbinger offers an array of electronic commerce
products and services for the World Wide Web. This includes the design and
creation of customized web sites and
 
                                       21
<PAGE>   23
 
the hosting of these sites. The hosting service is designed for large companies
that desire high levels of security, reliability, and customer support. Other
services included are domain name registration, usage statistics, web
registration with Internet directories and Common Gateway Interface development.
 
  Solutions for Small and Mid-Size Businesses
 
     TrustedLink Commerce.  The TrustedLink Commerce product family is designed
for small to mid-sized companies which are new to electronic commerce. The
products perform the critical tasks to create, format and electronically
transmit and receive business documents and data between trading partners. The
products convert a customer's documents and data into EDI format, translate the
document to a standard form for use with the designated trading partner,
transmit the information to the Harbinger networks, the Internet, or other third
party networks and convert EDI documents and data received from their trading
partners into a format that may be interpreted by the user's personal computer.
Additionally, TrustedLink Guardian, which provides encryption and decryption for
secure transmission over the Internet, can be used with TrustedLink Commerce for
Windows 95, NT Workstation and TrustedLink Enterprise for UNIX, enabling a
variety of communication options.
 
     STX Translation Software.  These EDI translation software programs for DOS
and Windows allow companies to exchange business documents electronically. The
products are network independent with a large number of predefined network
connections available. They provide for automatic operation of EDI functions
without operator intervention, including scheduling to send and/or receive EDI
transactions, translating application files to an EDI format or translating EDI
files to an application-file format, and printing or deleting transactions.
Products in the STX family include STFORMS which enables the user to customize
the format of EDI documents, STBAR which allows the entry of data via bar code
scanning and STSECURITY which allows users to perform secure EDI over the
Internet. Additionally, STMAP mapping integration software allows users to
download EDI data seamlessly from an application already integrated with STX and
to move data electronically between business programs and EDI applications.
 
     Harbinger Express.  Harbinger Express allows small and mid-size businesses
to perform EDI and electronic commerce using a web browser. The product is
designed for companies that conduct low EDI transaction volumes and have limited
requirements for integrating with other software applications. Harbinger Express
translates EDI documents into an HTML form which can be accessed by the trading
partner via the Internet. Harbinger Express users can also initiate EDI
documents simply by filling out a browser-based HTML form at the Harbinger
Express Website. The product converts the resulting document into EDI format and
transmits it to the receiving trading partner over the Harbinger networks or the
Internet.
 
     TrustedLink INP.  TrustedLink INP allows a user to establish an instant
presence on the Internet through the creation of a web site for the business
user. Users create their web site by entering information in an interview
format. The user can then preview their site using the included Netscape
Navigator software and publish the site on Harbinger's IVAS web hosting service.
TrustedLink INP includes an electronic catalog and purchase order system for
conducting commerce over the Internet.
 
     TrustedLink Banker.  TrustedLink Banker allows a user to access its bank
records through the Harbinger networks and translates documents and data through
industry standard formats including NACHA, BAI and Fedwire. Businesses use
TrustedLink Banker to access balance and transaction histories for various
financial accounts, perform electronic funds transfers between financial
accounts (within a single bank or among banks), register stop payments, write
checks, reconcile accounts, send and receive messages to and from financial
institutions, perform budgeting and cash flow analysis, and schedule activities
by means of an electronic calendar. The product is also used to perform direct
deposits into payroll accounts, fund tax payments and direct debit transactions
and
 
                                       22
<PAGE>   24
 
perform funds transfers. Banks and financial institutions access the Harbinger
network to exchange information, electronic mail and messages with their trading
partners.
 
     Trading Partner Packs and STX Forms Overlays.  Harbinger develops custom
software templates, known as Trading Partner Packs and STX Forms Overlays, to
conform with guidelines and parameters identified by the major purchasers and
suppliers within various trading communities. For example, Harbinger can
customize its software to utilize only a specified subset of the ANSI X.12 or
EDIFACT standard that the major trading partners have defined for the trading
relationship. In this way, each trading partner is assured that only the data
elements that the trading partners expect are sent and received. The Company
distributes these customized products to help hub companies expand the
acceptance of EDI among trading partners. Harbinger maintains an extensive
library of Trading Partner Packs and STX Forms Overlays.
 
  Services for Entire Trading Communities
 
     Value-Added Network Services.  Harbinger operates its VAN and IVAS as
value-added networks that provide the central point for document and data
receipt, translation and transmission and serve as a communication link between
the members of a trading community. With more than 38,000 revenue generating
customers, Harbinger believes that its VAN is one of the largest EDI networks in
the United States as measured by the number of billable subscribers. Harbinger
offers trading partners a wide range of network services including batch
communication of purchase orders, invoices, shipping confirmations, e-mail
between trading partners and electronic catalogs. The Company believes that its
value-added network offers several advantages to trading partners, including
protocol conversion, transmission speed conversion, flexibility in mail pick-up
and drop-off times, and security and reliability. The Company provides network
services pursuant to subscriber agreements which can be terminated by either
party without cause at any time with 30 days written notice. Customers are
required to pay for services in accordance with the then applicable service
fees, which include set-up fees, monthly mailbox fees and transaction fees. No
minimum revenue commitment or annual fee is required.
 
     Consulting and Programming Services.  Harbinger technical consultants work
with trading communities to create the functional specifications to develop
computer programs necessary to integrate EDI with other software applications.
This process, known as "mapping," requires the identification of internal data
file and record formats along with the creation of functional specifications to
integrate EDI with trading partner applications. Harbinger also provides
software programming services to trading communities to create the application
interface programs necessary to translate data into and out of EDI standards.
 
     Trading Partner Implementation and Certification.  Harbinger offers several
programs to assist its hub customers in maximizing the use of EDI and electronic
commerce among its trading partners. These programs communicate the advantages
of EDI and electronic commerce to potential trading partners of a major hub,
regardless of size, and include information seminars, support materials and the
trading partner certification program. This program assists trading partners in
installing, testing and confirming EDI capabilities with hub companies using the
Harbinger networks.
 
     Customer Training.  Harbinger offers training classes for various stages of
EDI implementation by trading partners. These classes provide instruction on the
use of the Company software products operating either alone or together with
other application software. The classes explain the basics of EDI and its
integration with other application software and provide basic information for
creating application interface programs to connect trading partners.
 
     Electronic Catalogs.  Harbinger offers its customers electronic catalog
technology, which allows purchasers to significantly streamline their purchasing
processes. This technology provides purchasers with online vendor catalogs in
real-time, offering up-to-date pricing, accurate descriptions, lead time and
other critical information, thereby saving companies the expense of maintaining
or otherwise accessing vendor information. Electronic catalog technology has
been applied in both
 
                                       23
<PAGE>   25
 
supply chain management initiatives for production goods and services, and
maintenance, repair and operating supplies for non-production goods and
services. Harbinger provides its solution in the form of an easy-to-use,
web-based application which allows users to search and source data from
electronic vendor catalogs and from their own internal inventory.
 
     Customer Support Services.  Harbinger provides extensive customer service
and support to trading partners on the use and operation of its software
products and the business processes associated with electronic commerce. The
Company's support of EDI communication standards enables its customer support
personnel to perform file transfers to analyze problems on a customer's computer
system and to transmit software or EDI standard updates to a customer where
necessary.
 
SALES AND MARKETING
 
     The Company's principal marketing strategy focuses on establishing
electronic trading communities and expanding the number of trading partners
using the Harbinger networks and software products. The Company seeks to target
trading communities composed of electronic trading partners in common industries
or markets conducting recurring business transactions. To achieve this
objective, the Company has developed a three-tiered sales and marketing program.
First, the Company identifies potential hub companies that either seek to
formulate an electronic commerce program, or that have made the decision to
implement an electronic commerce program. The Company representatives meet with
the hub company and discuss the procedure for establishing electronic commerce
relationships with trading partners. Second, the Company contacts the hub
company's trading partners through seminars and by telemarketing, informing
these parties of the electronic commerce requirements of the hub company and
implementation procedures. The Company schedules and conducts half-day
information seminars with potential trading partners of a major hub company
highlighting the benefits of electronic commerce, explaining the hub
organization's electronic commerce initiative, and demonstrating the Company's
products and services. Representatives of the hub company generally attend these
seminars to present their electronic commerce recommendations and requirements.
Third, Harbinger uses telemarketing, direct mail and advertising activities that
are targeted at potential customers who are not trading partners of a specific
hub. The Company's marketing and sales activities are centered around the
implementation of electronic commerce within these trading communities through
hub and spoke programs, particularly within selected vertical markets.
 
     Harbinger also markets and sells its products through distributors in the
United States and numerous international markets. Through the Marketing Partners
Program, the Company has established alliances with application software
developers, systems integrators and value-added resellers of computer products.
The Company's objective is to integrate Harbinger's products with those of its
Marketing Partners and to promote distribution of Harbinger software along with
products and services sold by its Marketing Partners. The Company markets and
distributes its TrustedLink Banker products and related services through
commercial banks and holding companies and bank processors, and directly to the
customers of certain banks and financial service organizations. The Company's
markets TrustedLink INP through a private-label distribution agreement with
Peachtree Software as well as through its World Wide Web site, from where
customers can download an evaluation version of the software.
 
     As of March 31, 1997, the Company employed approximately 185 sales and
marketing personnel who concentrate their efforts in direct sales of the
Company's software products and services. The Company is in the process of
training and educating these new sales personnel on the range of its products
and services and obtaining from them an understanding of the new markets made
available through the acquisitions. Management believes that the addition of
these sales persons will allow the Company to expand many of its product and
service offerings into additional trading communities. The Company's
compensation strategies are designed to reward sales personnel based upon sales
to new customers and the sale of additional products and services to existing
customers. In addition to the Company's internal sales and marketing personnel,
the Company markets its products through several licensees, distributors and
co-marketers.
 
                                       24
<PAGE>   26
 
                                   MANAGEMENT
 
EXECUTIVE OFFICERS AND DIRECTORS
 
     The executive officers and directors of the Company and their ages as of
July 1, 1997, are as follows:
 
<TABLE>
<CAPTION>
NAME                           AGE                        POSITION
- ----                           ---                        --------
<S>                            <C>   <C>
C. Tycho Howle...............  48    Chairman of the Board of Directors
David T. Leach...............  46    Chief Executive Officer and Director
James C. Davis...............  45    President and Chief Operating Officer and Director
James M. Travers.............  46    President, Harbinger Enterprise Solutions
Theodore C. Annis............  54    President, Harbinger SupplyTech
David A. Meeker..............  54    Senior Vice President, Sales
A. Gail Jackson..............  48    Senior Vice President, Harbinger SupplyTech
Joel G. Katz.................  33    Chief Financial Officer and Secretary
William D. Savoy(2)..........  32    Director
William B. King(2)...........  52    Director
Stuart L. Bell(1)(2).........  44    Director
Benn R. Konsynski(1).........  46    Director
Klaus Neugebauer(1)..........  59    Director
Ad Nederlof..................  51    Director
</TABLE>
 
- ---------------
 
(1) Member of the Audit Committee.
(2) Member of the Compensation Committee.
 
     Mr. Howle has served as Chairman of the Board of Directors of the Company
and its predecessors since 1983. Mr. Howle also served as the Chief Executive
Officer until March 1997. From 1981 to 1983, Mr. Howle was a consultant with
McKinsey & Company, Inc., a management consulting firm. From 1979 to 1981, Mr.
Howle was a Product Line Manager with the Hewlett-Packard Company. From 1973 to
1977, Mr. Howle was a project manager with Booz, Allen & Hamilton's Applied
Research Unit.
 
     Mr. Leach has served as Chief Executive Officer of the Company since March
1997 and a Director of the Company since February 1994. From February 1994 until
March 1997, Mr. Leach served as President and Chief Operating Officer of the
Company, and from June 1992 until February 1994, Mr. Leach was Group Executive
Vice President, Sales and Operations of the Company. Mr. Leach served as Senior
Vice President of Harbinger Computer Services, Inc. ("HCS") from 1988 until 1990
and was President of HCS from 1990 until its reorganization into Harbinger
Corporation in 1992. Prior to joining HCS, Mr. Leach was a consultant with
McKinsey & Company, Inc., a management consulting firm.
 
     Mr. Davis has served as Director of the Company since April 1997 and as
President and Chief Operating Officer of Harbinger since March 1997. From
January 1995 until March 1997, Mr. Davis served as President of Harbinger Group
Operations. Mr. Davis served as President of the Company from January 1989 until
December 1993, when Mr. Davis resigned as an officer and director of the
Company. Mr. Davis was Vice President and Senior Vice President of HCS from May
1984 until December 1988.
 
     Mr. Travers has served as President of Harbinger Enterprise Solutions since
January 1995. In this capacity, Mr. Travers manages the business operations
acquired in the TI Acquisition. From 1978 through 1994, Mr. Travers served in
various managerial positions with TI, including the position as Director of
Business Development for TI's Worldwide Applications Software Business and
General Manager of TI's EDI business unit from June 1992 through December of
1994.
 
     Mr. Annis has served as President of Harbinger SupplyTech since January
1997. Mr. Annis served as Chief Executive Officer and Treasurer of SupplyTech,
Inc. from its inception in 1984 until its merger with the Company in January
1997.
 
                                       25
<PAGE>   27
 
     Mr. Meeker has served as Senior Vice President, North American Sales since
January 1997. From January 1995 until January 1997, Mr. Meeker served as Vice
President, Sales of the Company and from September 1992 through December 1994,
Mr. Meeker served as Vice President, Sales for National Data Corp., a credit
card processing company. From January 1992 through August 1992, Mr. Meeker
served as Vice President, Sales and Marketing for Software Alternatives, a
computer software and systems vendor. From January 1990 to January 1992, Mr.
Meeker served as Manager, U.S. Channel Operations for IBM.
 
     Ms. Jackson has served as Senior Vice President of Harbinger SupplyTech
since March 1997 and as Vice President from January 1997 until March 1997. Ms.
Jackson served as President of SupplyTech, Inc. from its inception in 1984 until
its merger with the Company in January 1997.
 
     Mr. Katz has served as Chief Financial Officer since January 1997 and
Secretary since February 1994. He served as Vice President, Finance from January
1995 until January 1997 and as Senior Director of Finance from February 1994 to
January 1995. Mr. Katz joined Harbinger in 1990 as Controller and became
Director of Finance in December 1991. From 1985 to 1990, Mr. Katz was a
certified public accountant in the audit division of Arthur Andersen LLP.
 
     Mr. Savoy has been a director of the Company since May 1993. Under the
Company's policy statement regarding term limits for non-employee directors, Mr.
Savoy will be eligible to serve as a director through the date of the Company's
Annual Meeting to be held in 2001. Mr. Savoy has served as President of Vulcan
Northwest, Inc. since 1988. Mr. Savoy is also a director of Telescan, Inc.,
C/Net, Inc., U.S. Satellite Broadcasting Co., Inc. and Ticketmaster Corporation.
 
     Mr. King has been a director of the Company since January 1993. Under the
Company's policy statement regarding term limits for non-employee directors, Mr.
King will be eligible to serve as a director through the Company's Annual
Meeting to be held in 2001. Mr. King has served as Chairman of Private Business,
Inc., a banking software provider, since 1991. From 1986 until February 1995,
Mr. King served as Chairman of FISI-Madison Financial Corporation, Chairman of
CUC Europe, and served on the Board of Directors of CUC International.
 
     Mr. Bell has been a director of the Company since April 1995. Under the
Company's policy statement regarding term limits for non-employee directors, Mr.
Bell will be eligible to serve as a director through the date of the Company's
Annual Meeting to be held in 2003. Mr. Bell served as Executive Vice President
and Chief Financial Officer of CUC International from 1983 to January 1995, and
has served as Assistant to the Chief Executive Officer of CUC International
since February 1995. Mr. Bell is also a director of International Telephone Data
Services and Alarmguard Holdings, Inc.
 
     Dr. Konsynski has been a director of the Company since December 1996. Under
the Company's policy statement regarding term limits for non-employee directors,
Dr. Konsynski will be eligible to serve as a director through the date of the
Company's Annual Meeting to be held in 2004. Since 1993, Dr. Konsynski has been
the George S. Craft Professor of Business Administration at the Goizueta
Business School at Emory University. From 1987 to 1993, Dr. Konsynski was on the
faculty at Harvard Business School. Prior to the dissolution of HNS, Dr.
Konsynski was a member of the Board of Managers of HNS. Dr. Konsynski also
serves as a director of Tessco Technologies, Inc.
 
     Dr. Neugebauer has served as a Director of the Company since April 1997.
Under the Company's policy statement regarding term limits for non-employee
directors, Dr. Neugebauer will be eligible to serve as a director through the
date of the Company's Annual Meeting to be held in 2005. Dr. Neugebauer was a
co-founder of Softlab GmbH, an international software development company which
was sold to BMW AG in 1991. Dr. Neugebauer is a member of a number of German
industrial boards and acts as a strategic information technology advisor to the
State of Bavaria and the German Federal Government, and since 1991, has been a
partner in NSE Inc., an investment firm that specializes in the software
industry.
 
     Mr. Nederlof has served as a Director of the Company since April 1997.
Under the Company's policy statement regarding term limits for non-employee
directors, Mr. Nederlof will be eligible to serve as a director through the date
of the Company's Annual Meeting to be held in 2005. Mr. Nederlof currently
serves as an independent software consultant. Mr. Nederlof served as Vice
President of Oracle Northern Europe from 1994 to 1996, with responsibility for
all Northern European subsidiaries. From 1991 to 1994, he served as a Managing
Director of Oracle Nederland BV, Oracle's Dutch subsidiary.
 
                                       26
<PAGE>   28
 
                       PRINCIPAL AND SELLING SHAREHOLDERS
 
   
     The following table sets forth certain information regarding beneficial
ownership of the Company's Common Stock as of July 24, 1997, the number of
shares being offered and the beneficial ownership of the Company's Common Stock
upon consummation of the offering with respect to the following: (i) each
shareholder known by the Company to be the beneficial owner of more than five
percent of the Company's Common Stock, (ii) the Selling Shareholders, (iii) each
director, (iv) each executive officer, and (iv) all directors and executive
officers as a group.
    
 
   
<TABLE>
<CAPTION>
                                            SHARES BENEFICIALLY               SHARES BENEFICIALLY
                                              OWNED PRIOR TO                      OWNED AFTER
                                                OFFERING(1)       NUMBER OF       OFFERING(1)
                                            -------------------    SHARES     -------------------
NAME OF BENEFICIAL OWNER                     NUMBER     PERCENT    OFFERED     NUMBER     PERCENT
- ------------------------                    ---------   -------   ---------   ---------   -------
<S>                                         <C>         <C>       <C>         <C>         <C>
C. Tycho Howle(2).........................  1,206,117     6.2%       --       1,206,117     5.7%
David T. Leach(3).........................    482,104     2.5%       --         482,104     2.3%
James C. Davis(4).........................    308,333     1.6%       --         308,333     1.5%
Joel G. Katz(5)...........................     44,498     *          --          44,498     *
William B. King(6)........................     58,566     *          --          58,566     *
Stuart L. Bell(7).........................     37,125     *          --          37,125     *
William D. Savoy(8).......................  2,457,736    12.7%      500,000   1,957,736     9.2%
Benn R. Konsynski(9)......................     11,926     *          --          11,926     *
David A. Meeker(10).......................      9,700     *          --           9,700     *
James M. Travers(11)......................      8,400     *          --           8,400     *
Theodore C. Annis.........................    520,776     2.7%       --         520,776     2.5%
A. Gail Jackson(12).......................    908,552     4.7%       --         908,552     4.3%
Klaus Neugebauer(13)......................      3,000     *          --           3,000     *
Ad Nederlof(14)...........................     28,000     *          --          28,000     *
                                            ---------             ---------   ---------
All executive officers and directors as a
  group (14 persons)(15)..................  6,084,833    30.6%      500,000   5,584,833    25.8%
AXA Equity & Law Assurance Society
  Plc(16).................................  1,240,401     6.4%      300,000     940,401     4.5%
Orbis Pension Trustees Limited(17)........    882,369     4.6%      300,000     582,369     2.8%
Vulcan Ventures, Inc./Paul G. Allen(18)...  2,402,236    12.4%      500,000   1,902,236     9.0%
Warburg, Pincus Counsellors, LLC(19)......  1,276,350     6.6%       --       1,276,350     6.0%
          Total Shares Offered by Selling
            Shareholders..................                        1,100,000
</TABLE>
    
 
- ---------------
 
   * Less than 1% of the outstanding Common Stock.
 (1) Information with respect to "beneficial ownership" shown in the table above
     is based on information supplied by the directors, executive officers of
     the Company and filings made with the Commission or furnished to the
     Company by other shareholders.
 (2) Includes 838,910 shares held of record by Mr. Howle, 53,600 shares held of
     record by Mr. Howle's wife, an aggregate of 14,391 shares held by Mr.
     Howle's children, 173,400 shares held in a family limited partnership for
     the benefit of Mr. Howle, his wife and children, 75,000 shares held by a
     charitable remainder unitrust for the benefit of Mr. Howle, his wife and
     certain designated charities, 13,316 shares held in a charitable foundation
     created by Mr. Howle, and 37,500 shares subject to options exercisable
     within 60 days. Mr. Howle disclaims beneficial ownership of all such
     shares, other than the shares held of record by Mr. Howle or for his
     benefit. Mr. Howle's address is 1055 Lenox Park Boulevard, Atlanta, Georgia
     30319.
 (3) Includes 276,792 shares held jointly by Mr. Leach and his wife, and 205,312
     shares subject to options exercisable within 60 days.
 
                                       27
<PAGE>   29
 
 (4) Includes 224,896 shares held jointly by Mr. Davis and his wife, and 83,437
     shares subject to options exercisable within 60 days.
 (5) Includes 40,000 shares subject to options exercisable within 60 days.
 (6) Includes 39,000 shares subject to options exercisable within 60 days.
 (7) Includes 14,625 shares subject to options exercisable within 60 days.
 (8) Includes 34,875 shares subject to options exercisable within 60 days. Also
     includes 2,345,986 shares (1,845,986 shares after this offering) and 56,250
     shares subject to warrants exercisable within 60 days beneficially owned by
     Vulcan Ventures, Inc. and Paul G. Allen, as to which Mr. Savoy disclaims
     beneficial ownership. All 500,000 shares offered are being offered by
     Vulcan Ventures, Inc. and Paul G. Allen. Mr. Savoy's address is 110 110th
     Avenue, N.E., Suite 550, Bellevue, Washington 98004.
 (9) Includes 8,626 shares subject to options exercisable within 60 days.
(10) Includes 8,950 shares subject to options exercisable within 60 days.
(11) Includes 8,400 shares subject to options exercisable within 60 days.
   
(12) Includes 214,148 shares held jointly By Ms. Jackson and her husband. Ms.
     Jackson's address is 1000 Campus Drive, Ann Arbor, Michigan 48104.
    
(13) Includes 3,000 shares subject to options exercisable within 60 days.
(14) Includes 28,000 shares subject to options exercisable within 60 days.
(15) Includes 567,975 shares subject to options and warrants exercisable within
     60 days.
(16) Includes 1,218,651 shares (918,651 shares after this offering) and 3,000
     shares subject to options and 18,750 shares subject to warrants exercisable
     within 60 days. AXA Equity & Law Assurance Society Plc's address is 20
     Lincoln's Inn Field, London, England WC2A 3E5.
(17) Orbis Pension Trustees Limited's address is 1 Connaught Place, London,
     England W2 2DY.
(18) Includes 2,345,986 shares (1,845,986 shares after this offering) and 56,250
     shares subject to warrants exercisable within 60 days beneficially owned by
     Paul G. Allen. Excludes 34,875 shares held beneficially by Mr. Savoy, as to
     which Mr. Allen disclaims beneficial ownership. The address of Vulcan
     Ventures, Inc. and Paul G. Allen is 110 110th Avenue, N.E., Suite 550,
     Bellevue, Washington 98004.
(19) According to a Schedule 13G filed by Warburg, Pincus Counselors, Inc.
     ("Warburg, Pincus") dated January 9, 1997, Warburg, Pincus, a registered
     investment advisor beneficially owns 1,276,350 shares of Common Stock.
     According to the Schedule 13G, Warburg, Pincus has sole voting power to
     868,050 shares, shared voting power as to 197,850 shares and sole
     dispositive power as to 1,272,300 shares. Warburg, Pincus's address is 466
     Lexington Avenue, New York, New York 10017.
 
                                       28
<PAGE>   30
 
                          DESCRIPTION OF CAPITAL STOCK
 
     The authorized capital stock of the Company consists of 100,000,000 shares
of Common Stock, par value $.0001 per share, and 20,000,000 shares of Preferred
Stock. The following summary is qualified in its entirety by reference to the
Company's Amended and Restated Articles of Incorporation (the "Articles"), and
by the provisions of applicable law.
 
COMMON STOCK
 
     As of July 1, 1997, there were 19,292,886 shares of Common Stock
outstanding, held of record by approximately 180 shareholders. Holders of Common
Stock are entitled to one vote for each share held on all matters submitted to a
vote of shareholders and do not have cumulative voting rights. Accordingly,
holders of a majority of the shares of Common Stock entitled to vote in any
election of directors may elect all of the directors standing for election.
Holders of Common Stock are entitled to receive ratably such dividends, if any,
as may be declared by the Board of Directors out of funds legally available
therefor, subject to any preferential dividend rights of outstanding preferred
stock. Upon the liquidation, dissolution or winding up of the Company, the
holders of Common Stock are entitled to receive ratably the net assets of the
Company available after the payment of all debts and other liabilities and
subject to the prior rights of any outstanding preferred stockholders of Common
Stock, as such, have no preemptive, subscription, redemption or conversion
rights. The outstanding shares of Common Stock are, and the shares offered by
the Company in this offering will be, when issued and paid for, fully paid and
nonassessable. The rights, preferences and privileges of holders of Common Stock
are subject to, and may be adversely affected by, the rights of the holders of
shares of any series of preferred stock which the Company may designate and
issue from time to time in the future.
 
PREFERRED STOCK
 
     The Board of Directors is authorized, subject to certain limitations
prescribed by law, without further shareholder approval, to issue from time to
time up to an aggregate of 20,000,000 shares of preferred stock in one or more
series and to fix or alter the designations, preferences, rights and any
qualifications, limitations or restrictions on the shares of each such series
thereof, including the dividend rights, dividend rates, conversion rights,
voting rights, terms of redemption (including sinking fund provisions),
redemption price or prices, liquidation preferences and the number of shares
constituting any series or designations of such series. The issuance of
preferred stock may have the effect of delaying, deferring or preventing a
change of control of the Company. The only outstanding shares of preferred stock
are 4,000,000 shares of Zero Coupon Preferred Stock issued to an alliance
partner of the Company subject to performance vesting criteria. See Note 3 of
the Notes to Consolidated Financial Statements incorporated by reference in this
Prospectus. There are no other designated series of preferred stock.
 
CERTAIN CHARTER AND BYLAW PROVISIONS
 
     Shareholders' rights and related matters are governed by the Georgia
Business Corporation Code and the Company's Articles and its Amended and
Restated Bylaws (the "Bylaws"). Certain provisions of the Articles and Bylaws,
which are summarized below, could, either alone or in combination with each
other, have the effect of preventing a change in control of the Company or
making changes in management more difficult.
 
     Corporate Takeover Provisions.  The Company's Bylaws made applicable to the
Company provisions authorized by the Georgia Business Corporation Code relating
to business combinations with interested shareholders ("Corporate Takeover
Provisions"). The Corporate Takeover Provisions are designed to encourage any
person, before acquiring 10% of the Company's voting shares, to seek approval of
the Board of Directors for the terms of any contemplated business combination.
The Corporate Takeover Provisions will prevent for five years certain business
combinations with an
 
                                       29
<PAGE>   31
 
"interested shareholder" (as defined in the Corporate Takeover Provisions)
unless (i) prior to the time such shareholder became an interested shareholder
the Board of Directors approved either the business combination or the
transaction that resulted in the shareholder becoming an interested shareholder,
(ii) in the transaction that resulted in the shareholder becoming an interested
shareholder, the interested shareholder became the beneficial owner of at least
90% of the outstanding voting shares of the Company excluding, however, shares
owned by the Company's officers, directors, affiliates, subsidiaries and certain
employee stock plans or (iii) subsequent to becoming an interested shareholder,
such shareholder acquired additional shares resulting in the interested
shareholder becoming the owner of at least 90% of the Company's outstanding
voting shares and the business combination is approved by the holders of
majority of the Company's voting shares, excluding from said vote the stock
owned by the interested shareholder or by the Company's officers, directors,
affiliates, subsidiaries and certain employee stock plans.
 
     Shareholders of the Company who became interested shareholders prior to the
time of the adoption of the Corporate Takeover Provisions are not subject to
such provisions.
 
     The Board of Directors is divided into three classes, as nearly equal in
size as possible, with staggered three-year terms. One class is elected each
year. The classification of the Board of Directors could have the effect of
making it more difficult for a third party to acquire control of the Company.
 
     Constituency Considerations.  The Company's Articles provide for the right
of the Board of Directors to consider the interests of various constituencies,
including employees, customers, suppliers and creditors of the Company, as well
as the communities in which the Company is located, in addition to the interest
of the Company and its shareholders, in discharging their duties in determining
what is in the Company's best interests.
 
     Limitation of Directors' Liability.  The Company's Articles eliminate,
subject to certain exceptions, the personal liability of directors to the
Company or its shareholders for monetary damages for breaches of such directors'
duty of care or other duties as a director. The Articles do not provide for the
elimination of or any limitation on the personal liability of a director for (i)
any appropriation, in violation of the director's duties, of any business
opportunity of the Company, (ii) acts or omissions that involve intentional
misconduct or a knowing violation of law, (iii) unlawful corporate distributions
or (iv) any transaction from which the director received an improper benefit. In
addition, the Company's Bylaws provide broad indemnification rights to directors
and officers so long as the director or officer acted in a manner believed in
good faith to be in or not opposed to the best interest of the Company, and with
respect to criminal proceedings, if the director has no reasonable cause to
believe his or her conduct was unlawful. These provisions of the Articles and
Bylaws will limit the remedies available to a shareholder who is dissatisfied
with a Board decision protected by these provisions.
 
     The Articles provide that the affirmative vote of holders of at least 75%
of shares of Common Stock entitled to vote generally in the election of
directors, voting as a single voting group, is required to alter or amend the
provisions of the Articles providing for a staggered board of directors, or to
alter or amend the following provisions of the Bylaws: indemnification of
officers and directors, the vote required to amend the Bylaws, fair price
provisions, business combinations with interested shareholders, special meetings
of shareholders, the number of the Company's directors, removal of directors,
and who may fill vacancies within the board of directors.
 
TRANSFER AGENT AND REGISTRAR
 
     The transfer agent and registrar for the Common Stock is First Union
National Bank, Charlotte, North Carolina.
 
                                       30
<PAGE>   32
 
                                  UNDERWRITING
 
     Subject to the terms and conditions of the Underwriting Agreement, the
Underwriters named below (the "Underwriters") through their Representatives,
Alex. Brown & Sons Incorporated, The Robinson-Humphrey Company, Inc., Robertson,
Stephens & Company LLC and Interstate/Johnson Lane Corporation, have severally
agreed to purchase from the Company and the Selling Shareholders the following
respective numbers of shares of Common Stock at the initial public offering
price less the underwriting discounts and commission set forth on the cover page
of this Prospectus:
 
<TABLE>
<CAPTION>
                                                              NUMBER OF
                        UNDERWRITER                            SHARES
                        -----------                           ---------
<S>                                                           <C>
Alex. Brown & Sons Incorporated.............................
The Robinson-Humphrey Company, Inc..........................
Robertson, Stephens & Company LLC...........................
Interstate/Johnson Lane Corporation.........................
                                                              ---------
Total.......................................................  2,900,000
                                                              =========
</TABLE>
 
     The Underwriting Agreement provides that the obligations of the
Underwriters are subject to certain conditions precedent and that the
Underwriters will purchase all shares of the Common Stock offered hereby if any
of such shares are purchased.
 
     The Company and Selling Shareholders have been advised by the Underwriters
that the Underwriters propose to offer the shares of Common Stock to the public
at the public offering price set forth on the cover page of this Prospectus, and
to certain dealers at such price less a concession not in excess of $
per share. The Underwriters may allow, and such dealers may reallow, a
concession not in excess of $          share to certain other dealers. After the
public offering, the offering price and other selling terms may be changed by
the Representatives of the Underwriters.
 
     The Company and the Selling Shareholders have granted to the Underwriters
an option, exercisable not later than 30 days after the date of this Prospectus,
to purchase up to 435,000 additional shares of Common Stock at the public
offering price less the underwriting discounts and commissions set forth on the
cover page of this Prospectus. To the extent that the Underwriters exercise such
option, each of the Underwriters will have a firm commitment to purchase
approximately the same percentage thereof that the number of shares of Common
Stock to be purchased by it shown in the above table bears to 2,900,000, and the
Company and the Selling Shareholders will be obligated, pursuant to the option,
to sell such shares to the Underwriters. The Underwriters may exercise such
option only to cover over-allotments made in connection with the sale of the
Common Stock offered hereby. If purchased, the Underwriters will offer such
additional shares on the same terms as those on which the 2,900,000 shares are
being offered.
 
     In connection with the offering, certain Underwriters may engage in passive
market making transactions in the Common Stock on the Nasdaq National Market
immediately prior to the commencement of sales in the offering in accordance
with Rule 103 of Regulation M. Passive market making consists of displaying bids
on the Nasdaq National Market limited by the bid prices of independent market
makers and making purchases limited by such prices and effected in response to
order flow. Net purchases by a passive market maker on each day are limited to a
specified percentage of the passive market maker's average daily trading volume
in the Common Stock during a specified period and must be discontinued when such
limit is reached. Passive market making may stabilize the market price of the
Common Stock at a level above that which might otherwise prevail and, if
commenced, may be discontinued at any time.
 
     Subject to applicable limitations, the Underwriters, in connection with the
offering, may place bids for or make purchases of the Common Stock in the open
market or otherwise, for long or short account, or cover short positions
incurred, to stabilize, maintain or otherwise prevail in the open market. There
can be no assurance that the price of the Common Stock will be stabilized, or
that stabilizing, if commenced, will not be discontinued at any time. Subject to
applicable limitations,
 
                                       31
<PAGE>   33
 
the Underwriters may also place bids or make purchases on behalf of the
underwriting syndicate to reduce a short position created in connection with the
offering. The Underwriters are not required to engage in these activities and
may end these activities at any time.
 
     The Company and the Selling Shareholders have agreed to indemnify the
Underwriters against certain liabilities, including liabilities under the
Securities Act.
 
   
     The Selling Shareholders, directors, executive officers of the Company, and
certain of their respective family members, who will hold in the aggregate
6,517,878 shares of Common Stock, and options and warrants that are exercisable
within 60 days of July 1, 1997 to purchase an aggregate of 589,725 shares of
Common Stock of the Company after the offering, have agreed not to offer, sell
or otherwise dispose of 6,925,234 of such shares of Common Stock for a period of
90 days after the date of this Prospectus, without the prior written consent of
the Representatives of the Underwriters. The Company has agreed not to offer,
sell or otherwise dispose of any shares of Common Stock for a period of 90 days
from the date of this Prospectus without the prior consent of the
Representatives of the Underwriters, except that the Company may issue shares of
Common Stock under its current stock option plans and stock purchase plan.
    
 
                                 LEGAL MATTERS
 
     The validity of the Common Stock offered hereby and the issuance thereof
will be passed upon for the Company by Morris, Manning & Martin, L.L.P.,
Atlanta, Georgia. Certain legal matters will be passed upon for the Underwriters
by Piper & Marbury L.L.P., Baltimore, Maryland.
 
                       CERTAIN FORWARD LOOKING STATEMENTS
 
     This Prospectus (including the documents incorporated herein by reference)
contains or may contain certain forward-looking statements and information that
are based on beliefs of, and information currently available to, the Company's
management as well as estimates and assumptions made by the Company's
management. When used in this Prospectus, words such as "anticipate," "believe,"
"estimate," "expect," "future," "intend," "plan" and similar expressions as they
relate to the Company or the Company's management, identify forward-looking
statements. Such statements reflect the current views of the Company with
respect to future events and are subject to certain risks, uncertainties and
assumptions relating to the Company's operations and results of operations,
competitive factors and pricing pressures, shifts in market demand, the
performance and needs of the industries served by the Company, the costs of
product development and other risks and uncertainties, including the risk and
uncertainties identified in risk factors. Should one or more of these risks or
uncertainties materialize, or should the underlying assumptions prove incorrect,
actual results or outcomes may vary significantly from those anticipated,
believed, estimated, expected, intended or planned.
 
                                    EXPERTS
 
     The consolidated financial statements and financial statement schedule of
the Company as of December 31, 1996 and 1995, and for each of the years in the
two-year period ended December 31, 1996, have been incorporated by reference
herein and in the registration statement from the Company's Current Report on
Form 8-K filed on July 1, 1997 in reliance upon the report of KPMG Peat Marwick
LLP, independent certified public accountants, incorporated by reference herein
and in the registration statement and upon the authority of said firm as experts
in accounting and auditing. The report of KPMG Peat Marwick LLP expressed
reliance on the report of other auditors as it relates to the amounts included
for SupplyTech, Inc. and SupplyTech International, LLC for 1995.
 
     The financial statements of Harbinger NET Services, LLC as of December 31,
1996 and 1995 and for the periods ended December 31, 1996 and 1995 have been
incorporated by reference herein and in the registration statement from the
Company's Current Report on Form 8-K/A Amendment No. 1
 
                                       32
<PAGE>   34
 
filed on March 14, 1997 in reliance upon the report of KPMG Peat Marwick LLP,
independent certified public accountants, incorporated by reference herein and
in the registration statement and upon the authority of said firm or experts in
accounting and auditing.
 
     The combined financial statements of SupplyTech, Inc. and SupplyTech
International, LLC as of December 31, 1996 and for the year then ended have been
incorporated by reference herein and in the registration statement from the
Company's Current Report on Form 8-K/A Amendment No. 1 filed on March 18, 1997
in reliance upon the report of KPMG Peat Marwick LLP, independent certified
public accountants, incorporated by reference herein and in the registration
statement and upon the authority of said firm as experts in accounting and
auditing.
 
     The financial statements and schedule of the Company for the year ended
December 31, 1994, which have been incorporated by reference herein and in the
registration statement from the Company's Current Report on Form 8-K filed on
July 1, 1997 have been audited by Arthur Andersen LLP, independent public
accountants, as indicated in their report with respect thereto, and are
incorporated by reference herein and in the registration statement in reliance
upon the authority of said firm as experts in accounting and auditing in giving
said reports.
 
     The combined financial statements of SupplyTech, Inc. and SupplyTech
International, LLC as of December 31, 1995 and for each of the years in the
two-year period ended December 31, 1995 have been incorporated by reference
herein and in the registration statement from the Company's Current Report on
Form 8-K/A Amendment No. 1 filed on March 18, 1997 in reliance upon the report
of Ciulla, Smith & Dale, LLP, independent certified public accountants,
incorporated by reference herein and in the registration statement and upon the
authority of said firm as experts in accounting and auditing.
 
     The consolidated financial statements of NTEX Holding, B.V. as of December
31, 1995 and for the year then ended, have been incorporated by reference herein
and in the registration statement from the Company's Current Report on Form
8-K/A Amendment No. 1 filed on June 17, 1996 in reliance upon the report of
Moret Ernst & Young Accountants, independent certified public accountants,
incorporated by reference herein and in the registration statement and upon the
authority of said firm as experts in accounting and auditing.
 
     The financial statements of INOVIS GmbH & Co. computergestuzte
Informationssysteme as of December 31, 1995, and for the year then ended have
been incorporated by reference herein and in the registration statement from the
Company's Current Report of Form 8-K/A Amendment No. 1 filed on July 1, 1996 in
reliance upon the report of KPMG Deutsche TreuhandGesellschaft AG, independent
certified public accountants, incorporated by reference herein and in the
registration statement and upon the authority of said firm as experts in
accounting and auditing.
 
     The consolidated financial statements of Harbinger N.V. and subsidiaries as
of December 31, 1995, 1994, and 1993, and for the two years ended December 31,
1995, and 1994, and the one month ended December 31, 1993, have been
incorporated by reference herein and in the registration statement from the
Company's Current Report on Form 8-K/A Amendment No. 1 filed on July 2, 1996 in
reliance upon the report of KPMG Accountants N.V., independent certified public
accountants, incorporated by reference herein and in the registration statement
and upon the authority of said firm as experts in accounting and auditing.
 
     The statement of operations of EDI (formerly a business unit of Texas
Instruments, Incorporated) for the year ended December 31, 1994, incorporated by
reference in this Prospectus and registration statement, has been audited by
Ernst & Young LLP, independent auditors, as set forth in their report thereon
included in the Company's registration statement (Form S-1, No. 33-93804). Such
financial statements have been incorporated herein by reference in reliance upon
such report given upon the authority of such firm as experts in accounting and
auditing.
 
                                       33
<PAGE>   35
 
                             AVAILABLE INFORMATION
 
     This Prospectus constitutes a part of a Registration Statement which the
Company has filed with the Commission under the Securities Act of 1933, as
amended, with respect to the Shares of Common Stock. This Prospectus omits
certain of the information contained in the Registration Statement, and
reference is hereby made to the Registration Statement and related exhibits
thereto for further information with respect to the Company and the securities
offered hereby. Such additional information can be obtained from the
Commission's office in Washington, D.C. Any statements contained herein
concerning the provisions of any documents are not necessarily complete, and, in
each instance, reference is made to the copy of such document filed as an
exhibit to the Registration Statement or otherwise filed with the Commission.
Each such statement is qualified in its entirety by such reference.
 
     The Company is subject to the informational requirements of the Securities
Exchange Act of 1934 and files reports and other information with the Securities
and Exchange Commission (the "Commission") in accordance therewith. Such
reports, proxy statements, and other information filed by the Company are
available for inspection and copying at the public reference facilities of the
Commission at Room 1024, 450 Fifth Street, N.W., Judiciary Plaza, Washington,
D.C. 20549, and at the Commission's Regional Offices located at Room 1028, Jacob
K. Javits Federal Building, 26 Federal Plaza, New York, New York 10278 and Room
3190, Kluczynski Federal Building, 230 South Dearborn Street, Chicago, Illinois
60604. Copies of such material may be obtained by mail from the Public Reference
Section of the Commission at 450 Fifth Street, N.W., Judiciary Plaza,
Washington, D.C. 20549, at prescribed rates. The Commission maintains a World
Wide Web site on the Internet that contains reports, proxy and information
statements and other information regarding registrants which file electronically
with the Commission at http://www.sec.gov. The Company's common stock is listed
on the Nasdaq Stock Market. In addition to the addresses listed above, reports,
proxy statements, and other information concerning the Company can be inspected
at the offices of the Nasdaq Stock Market.
 
               INCORPORATION OF CERTAIN INFORMATION BY REFERENCE
 
     The following documents filed by the Company with the Commission are
incorporated by reference in this Prospectus: (i) the Company's Annual Report on
Form 10-K for the year ended December 31, 1996; (ii) the Company's Proxy
Statement dated April 2, 1997; (iii) the Company's Quarterly Report on Form 10-Q
for the quarter ended March 31, 1997; (iv) the description of the Common Stock
of the Company which is contained in the Company's Form 8-A/A Amendment No. 1
dated August 21, 1995, as incorporated by reference therein from the Company's
Pre-Effective Amendment No. 4 to its Registration Statement on Form S-1 dated
August 18, 1995; (v) the statement of operations of EDI (formerly a business
unit of Texas Instruments, Incorporated) for the year ended December 31, 1994,
included in the Company's Registration Statement (File No. 33-93804) on Form
S-1; (vi) the Company's Current Report on Form 8-K dated April 4, 1996, and
filed on April 18, 1996, as amended by its Current Report on Form 8-K/A
Amendment No. 1 filed June 17, 1996; (vii) the Company's Current Report on Form
8-K dated April 19, 1996, and filed on May 2, 1996, as amended by its Current
Report on Form 8-K/A Amendment No. 1 filed July 1, 1996; (viii) the Company's
Current Report on Form 8-K dated April 20, 1996, and filed on May 3, 1996, as
amended by its Current Report on Form 8-K/A Amendment No. 1 filed July 2, 1996;
(ix) the Company's Current Report on Form 8-K dated January 1, 1997, and filed
on January 15, 1997, as amended by its Current Report on Form 8-K/A Amendment
No. 1 filed March 14, 1997; (x) the Company's Current Report on Form 8-K dated
January 3, 1997, and filed on January 16, 1997, as amended by its Current Report
on Form 8-K/A Amendment No. 1 filed March 18, 1997; (xi) the Company's Current
Report on Form 8-K dated April 28, 1997, and filed on April 28, 1997; and (xii)
the Company's Current Report on Form 8-K dated July 1, 1997, and filed on July
1, 1997.
 
                                       34
<PAGE>   36
 
     All documents filed by the Company pursuant to Sections 13(a), 13(c), 14 or
15(d) of the Exchange Act subsequent to the date of this Prospectus and prior to
the termination of the offering of the Shares offered hereby shall be deemed to
be incorporated by reference into this Prospectus and to be a part hereof. The
Company hereby undertakes to provide without charge to each person to whom this
Prospectus has been delivered, upon the written or oral request of any such
person, a copy of any and all of the foregoing documents incorporated herein by
reference (other than exhibits to such documents which are not specifically
incorporated by reference into the information that this Prospectus
incorporates). Written or telephone requests should be directed to Investor
Relations Department, Harbinger Corporation, 1055 Lenox Park Boulevard, Atlanta,
Georgia 30319, telephone number (404) 467-3000.
 
                                       35
<PAGE>   37
 
======================================================
 
     NO PERSON HAS BEEN AUTHORIZED IN CONNECTION WITH THE OFFERING MADE HEREBY
TO GIVE ANY INFORMATION OR TO MAKE ANY REPRESENTATIONS NOT CONTAINED IN THIS
PROSPECTUS AND, IF GIVEN OR MADE, SUCH INFORMATION OR REPRESENTATION MUST NOT BE
RELIED UPON AS HAVING BEEN SO AUTHORIZED BY THE COMPANY, ANY SELLING SHAREHOLDER
OR ANY UNDERWRITER. THIS PROSPECTUS DOES NOT CONSTITUTE ANY OFFER TO SELL OR A
SOLICITATION OF AN OFFER TO BUY ANY OF THE SECURITIES OFFERED HEREBY TO ANY
PERSON OR BY ANYONE IN ANY JURISDICTION IN WHICH IT IS UNLAWFUL TO MAKE ANY SUCH
OFFER OR SOLICITATION. NEITHER THE DELIVERY OF THIS PROSPECTUS NOR ANY SALE MADE
HEREUNDER SHALL, UNDER ANY CIRCUMSTANCES, CREATE ANY IMPLICATION THAT THE
INFORMATION HEREIN IS CORRECT AS OF ANY DATE SUBSEQUENT TO THE DATE HEREOF.
 
                               ------------------
 
                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                        PAGE
                                        ----
<S>                                     <C>
Risk Factors..........................    6
Use of Proceeds.......................   13
Price Range of Common Stock...........   13
Dividend Policy.......................   13
Capitalization........................   14
Selected Financial Data...............   15
Business..............................   17
Management............................   25
Principal and Selling Shareholders....   27
Description of Capital Stock..........   29
Underwriting..........................   31
Legal Matters.........................   32
Certain Forward Looking Statements....   32
Experts...............................   32
Available Information.................   34
Incorporation of Certain Information
  by Reference........................   34
</TABLE>
 
                               ------------------
 
======================================================
 
======================================================
                                2,900,000 SHARES
                                (LOGO) HARBINGER
                                  COMMON STOCK
                              ------------------- 
                                   PROSPECTUS
                              -------------------
                               ALEX. BROWN & SONS
                                 INCORPORATED
                             THE ROBINSON-HUMPHREY
                                 COMPANY, INC.
                             ROBERTSON, STEPHENS &
                                    COMPANY
                            INTERSTATE/JOHNSON LANE
                                  CORPORATION
 
                                 July   , 1997
======================================================
<PAGE>   38
                                     PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS



ITEM 14.  OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.

         None of the expenses relating to the registration of Shares will be 
borne by the Selling Shareholders. The expenses of registration are estimated 
to be as follows:

<TABLE>
       <S>                                                                                 <C>

       Securities and Exchange Commission registration fee..............................   $28,994.29
       National Association of Securities Dealers, Inc. filing fee......................    10,368.00
       Nasdaq National Market additional listing fee....................................    17,500.00
       Accountants' fees and expenses...................................................    65,000.00
       Legal fees and expenses..........................................................   130,000.00
       Printing expenses................................................................    50,000.00
       Miscellaneous....................................................................    48,137.71
                                                                                          -----------
                   Total Expenses.......................................................  $350,000.00
</TABLE>


ITEM 15. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         The Georgia Business Corporation Code permits a corporation to
eliminate or limit the personal liability of a director to the corporation or
its shareholders for monetary damages for breach of duty of care of other duty
as a director, provided that no provision shall eliminate or limit the liability
of a director: (A) for an appropriation, in violation of his duties, of any
business opportunity of the corporation; (B) for acts or omissions which involve
intentional misconduct or a knowing violation of law; (C) for unlawful corporate
distributions; or (D) for any transaction from which the director received an
improper personal benefit. This provision pertains only to breaches of duty by
directors in their capacity as directors (and not in any other corporate
capacity, such as officers) and limits liability only for breaches of fiduciary
duties under Georgia corporate law (and not for violation of other laws, such as
the federal securities laws). The Company's Amended and Restated Articles of
Incorporation (the "Restated Articles") exonerate the Company's directors from
monetary liability to the extent permitted by this statutory provision.

         The Company's Restated Articles and Amended and Restated Bylaws (the
"Restated Bylaws") also provide that the Company shall indemnify any person who
was or is a party or is threatened to be made a party to any threatened, pending
or completed action, suit or proceeding, whether civil, criminal, administrative
or investigative (including any action by or in the right of the Company), by
reason of the fact that such person is or was a director or officer of the
Company, or is or was serving at the request of the Company as a director or
officer of another corporation, partnership, joint venture, trust or other
enterprise, against expenses (including reasonable attorneys' fees), judgments,
fines, and amounts paid in settlement actually and reasonably incurred by such
person in connection with such action, suit or proceeding, if such person acted
in good faith and in a manner such person reasonably believed to be in or not
opposed to the best interests of the Company (and with respect to any criminal
action or proceeding, if such person had no reasonable cause to believe such
person's conduct was unlawful), to the maximum extent permitted by, and in the
manner provided by, the Georgia Business Corporation Code.

         Notwithstanding any provisions of the Company's Restated Articles and
Bylaws to the contrary, the Georgia Business Corporation Code provides that the
Company shall not indemnify a director or officer for any liability incurred in
a proceeding in which the director is adjudged liable to the Company or is
subjected to injunctive relief in favor of the Company: (1) for any
appropriation, in violation of his duties, of any business opportunity of the
Company; (2) for acts or omissions which involve intentional misconduct or a
knowing violation of law; (3) for unlawful corporate distributions; or (4) for
any transaction from which the director or officer received an improper personal
benefit.

                                      II-1
<PAGE>   39

The officers and directors of the Company are entitled to indemnification by the
Selling Shareholders against any cause of action, loss, claim, damage or
liability to the extent it arises out of or is based upon the failure of the
Selling Shareholders (or his donees, legatees, or pledgees) and each underwriter
to comply with the Prospectus delivery requirements under the federal securities
laws or any applicable state securities laws or upon any untrue statement or
alleged untrue statement or omission or alleged omission made in this
Registration Statement and the Prospectus contained herein, as the same shall be
amended or supplemented, made in reliance upon or in conformity with written
information furnished to the Company by such Selling Shareholder or such
underwriter.

ITEM 16.    LIST OF EXHIBITS.

     The following exhibits are filed as part of, or are incorporated by
reference into, this report on Form S-3:

   
<TABLE>
<CAPTION>

        EXHIBIT
        NUMBER                                             DESCRIPTION
   --------------   ----------------------------------------------------------------------------------------
          <S>       <C>                                                                                     

          1.1       Form of Underwriting Agreement

          2.1       Share Purchase Agreement effective as of March 31, 1996
                    among F.J. Nederlof B.V., H.W.I. Bol, Arthur Nederlof B.V.
                    (the "NTEX Shareholders") and the Company (incorporated by
                    reference to Exhibit 2(a) filed with the Company's Current
                    Report on Form 8-K dated April 18, 1996).

          2.2       Share Purchase Agreement effective as of March 31, 1996
                    among Jakob Karszt, Helmut Grimm, Hans Rauh, Nikolai Preis,
                    Ulrich Rehn, Eugen Volbers, Jurgen M. Diet, Wolffried Stucky
                    and Jorg Blum (the "INOVIS Shareholders") and the Company
                    (incorporated by reference to Exhibit 2(a) filed with the
                    Company's Current Report on Form 8-K dated May 2, 1996).

          2.3       Debenture Purchase Agreement effective as of January 1, 1997
                    between BellSouth Telecommunications, Inc. and the Company
                    (incorporated by reference to Exhibit 2.1 filed with the
                    Company's Current Report on Form 8-K dated January 15,
                    1997).

          2.4       Merger Agreement dated January 3, 1997 among SupplyTech,
                    Inc., Harbinger Acquisition Corporation II and the Company
                    (incorporated by reference to Exhibit 2.1 filed with the
                    Company's Current Report on Form 8-K dated January 16,
                    1997).

          2.5       Agreement and Plan of Reorganization between and among
                    Vulcan Ventures, Inc., AXA Equity & Law Life Assurance
                    Society, Ltd. (the "HNV Shareholders"), Harbinger N.V. and
                    the Company effective as of March 29, 1996 (incorporated by
                    reference to Exhibit 2(a) filed with the Company's Current
                    Report on Form 8-K dated May 3, 1996).

          3.1       Amended and Restated Articles of Incorporation of the
                    Company (incorporated by reference to Exhibit 3.1 to the
                    Company's Registration Statement on Form S-1 (File 33-93804)
                    declared effective on August 22, 1995).

          3.2       Amended and Restated Bylaws of the Company (incorporated by 
                    reference to Exhibit 3.2 to the Company's Annual Report
                    on Form 10-K for the year ended December 31, 1996).

          4.1       Provisions of the Amended and Restated Articles of
                    Incorporation and Amended and Restated Bylaws of the Company
                    defining rights of the holders of the Common Stock
                    (incorporated by reference to Exhibits 3.1 through 3.4 to
                    the Company's Registration Statement on Form S-1 (File No.
                    33-93804) declared effective on August 22, 1995).


</TABLE>
    

                                      II-2
<PAGE>   40


   
<TABLE>
<CAPTION>

        EXHIBIT
        NUMBER                                DESCRIPTION
   ---------------  -------------------------------------------------------------------------
          <S>       <C> 

          4.2       Specimen Stock Certificate (incorporated by reference to
                    Exhibit 4.3 to the Company's Registration Statement on Form
                    S-1 (File 33-93804)).

          4.3       Form of Registration Rights Agreement effective March 31,
                    1996 between the Company and each of the NTEX Shareholders
                    (incorporated by reference to Exhibit 2(a) filed with the
                    Company's Current Report on Form 8-K dated April 18, 1996).

          4.4       Form of Registration Rights Agreement effective March 29,
                    1996 between each of the Harbinger N.V. Shareholders and the
                    Company (incorporated by reference to Exhibit 2(a) filed
                    with the Company's Current Report on Form 8-K dated May 3,
                    1996).

          4.5       Form of Warrant issued to former Harbinger N.V. Shareholders
                    on July 18, 1996 (incorporated by reference to Exhibit 4.5
                    to the Company's Annual Report on Form 10-K for the year
                    ended December 31, 1996).

          4.6       Registration Rights Agreement among the former shareholders
                    of SupplyTech, Inc. and the Company effective January 3,
                    1997 (incorporated by reference to Exhibit 4.1 filed with
                    the Company's Current Report on Form 8-K dated January 16,
                    1997).

          4.7       Form of Warrant issued to former INOVIS Shareholders on
                    April 19, 1996 (incorporated by reference to Exhibit 2(a)
                    filed with the Company's Current Report on Form 8-K dated
                    July 1, 1996).

          4.8       Form of Registration Rights Agreement effective March 31,
                    1996 between each of the former INOVIS Shareholders and the
                    Company (incorporated by reference to Exhibit 2(a) filed
                    with the Company's Current Report on Form 8-K dated July 1,
                    1996).

          5.1**     Form of opinion of Morris, Manning & Martin, L.L.P. as to 
                    the legality of the securities being registered.

          10.1      Promissory Note for $10,000,000 payable by the Company to
                    NationsBank of Georgia, N.A. dated April 16, 1997
                    (incorporated by reference to Exhibit 10.1 filed to the
                    Company's Registration Statement on Form S-3 (File No.
                    333-30501) declared effective on July 3, 1997).

          10.2      Loan Agreement between the Company and NationsBank of
                    Georgia, N.A. dated as of August 15, 1994, with First
                    Amendment dated as of May 2, 1995 (incorporated by reference
                    to Exhibit 10.13 filed to the Company's Registration
                    Statement on Form S-1 (File 33-93804) declared effective on
                    August 22, 1995).


</TABLE>
    



                                      II-3
<PAGE>   41

   
<TABLE>
<CAPTION>

        EXHIBIT
        NUMBER                                DESCRIPTION
   ---------------  ----------------------------------------------------------------------------------------
          <S>       <C>

          10.3      Second Amendment to Loan Agreement between the Company and
                    NationsBank, National Association (South) dated April 16,
                    1997 (incorporated by reference to Exhibit 10.3 filed to the
                    Company's Registration Statement on Form S-3 (File No.
                    333-30501) declared effective on July 3, 1997).

          10.4      Employment Agreement between the Company and Mr. James M.
                    Travers effective as of February 1, 1995 with letter from
                    the Company to Mr. Travers dated December 27, 1994
                    (incorporated by reference to Exhibit 10.14 filed to the
                    Company's Registration Statement on Form S-1 (File 33-93804)
                    declared effective on August 22, 1995).

          10.5**    Employment Agreement between the Company and Mr. James C.
                    Davis effective as of July 1, 1997.

          10.6      Assignment of Invention and Patents Thereon (Patent
                    5,367,664) by Texas Instruments, Incorporated ("TI") to the
                    Company dated January 12, 1995 as recorded with United
                    States Patent and Trademark Office on March 13, 1995
                    (incorporated by reference to Exhibit 10.16 filed to the
                    Company's Registration Statement on Form S-1 (File 33-93804)
                    declared effective on August 22, 1995). 

          10.7      U.S. Patent 5,367,664 issued November 22, 1994 (incorporated
                    by reference to Exhibit 10.17 filed to the Company's
                    Registration Statement on Form S-1 (File 33-93804) declared
                    effective on August 22, 1995).

          10.8      Assignment of Invention and Patents Thereon (Application
                    07/502,955) by TI to the Company dated January 12, 1995 as
                    recorded with United States Patent and Trademark Office on
                    March 13, 1995 (incorporated by reference to Exhibit 10.18
                    filed to the Company's Registration Statement on Form S-1
                    (File 33-93804) declared effective on August 22, 1995).

          10.9      Asset Purchase Agreement between the Company and TI dated as
                    of December 31, 1994 (incorporated by reference to Exhibit
                    10.19 filed to the Company's Registration Statement on Form
                    S-1 (File 33-93804) declared effective on August 22, 1995).

          10.10     Employment Agreement between the Company and Mr. David A.
                    Meeker effective as of December 21, 1994 (incorporated by
                    reference to Exhibit 10.21 filed to the Company's
                    Registration Statement on Form S-1 (File 33-93804) declared
                    effective on August 22, 1995).

          10.11     401(k) Profit Sharing Plan amended and restated effective as
                    of September 1, 1994; original effective date October 1,
                    1991 (incorporated by reference to Exhibit 10.24 filed to
                    the Company's Registration Statement on Form S-1 (File
                    33-93804) declared effective on August 22, 1995).

          10.12     Employment Agreement between the Company and Mr. C. Tycho
                    Howle effective as of March 4, 1997 (incorporated by
                    reference to Exhibit 10.11 to the Company's Annual Report on
                    Form 10-K for the year ended December 31, 1996).
</TABLE>
    

                                      II-4
<PAGE>   42
   
<TABLE>
<CAPTION>

        EXHIBIT
        NUMBER                                DESCRIPTION
   --------------   -----------------------------------------------------------------------------------------
          <S>       <C>
          10.13**   First Amendment to Employment Agreement between the Company
                    and Mr. C. Tycho Howle effective as of July 1, 1997.

          10.14     Employment Agreement between the Company and Mr. Joel G.
                    Katz effective as of March 7, 1994 (incorporated by
                    reference to Exhibit 10.26 filed to the Company's
                    Registration Statement on Form S-1 (File 33-93804) declared
                    effective on August 22, 1995).

          10.15**   Employment Agreement between the Company and Mr. David T.
                    Leach effective as of July 1, 1997.

          10.16     License and Service Agreement between the Company and Bank
                    of America National Trust and Savings Association dated as
                    of February 18, 1994 (incorporated by reference to Exhibit
                    10.29 filed to the Company's Registration Statement on Form
                    S-1 (File 33-93804) declared effective on August 22, 1995).

          10.17     Amended and Restated 1993 Stock Option Plan for Nonemployee
                    Directors effective as of August 11, 1993 (incorporated by
                    reference to Exhibit 10.33 filed to the Company's
                    Registration Statement on Form S-1 (File 33-93804) declared
                    effective on August 22, 1995).

          10.18     Third Amendment to Amended and Restated 1993 Stock Option
                    Plan for Nonemployee Directors (incorporated by reference to
                    Exhibit 10.17 to the Company's Annual Report on Form 10-K
                    for the year ended December 31, 1996).

          10.19     Co-Marketing Agreement between the Company and Sprint
                    Communications Company Limited Partnership of Delaware made
                    as of August 9, 1993 (incorporated by reference to Exhibit
                    10.34 filed to the Company's Registration Statement on Form
                    S-1 (File 33-93804) declared effective on August 22, 1995).

          10.20     Lease between the Company and Lenox Park Development 1 L.P.
                    for office located at 1055 Lenox Park Boulevard, Atlanta,
                    Georgia dated July 16, 1992 with First Amendment dated July
                    22, 1993 and Second Amendment dated December 27, 1993
                    (incorporated by reference to Exhibit 10.38 filed to the
                    Company's Registration Statement on Form S-1 (File 33-93804)
                    declared effective on August 22, 1995).

          10.21     Amended and Restated 1989 Stock Option Plan effective as of
                    April 15, 1992 (incorporated by reference to Exhibit 10.39
                    filed to the Company's Registration Statement on Form S-1
                    (File 33-93804) declared effective on August 22, 1995).

          10.22+    Harbinger Business Financial Management System License
                    Agreement between the Company as assignee of Harbinger
                    Computer Services, Inc. and Barnett Banks, Inc. dated
                    November 18, 1991 with amendment dated May 21, 1992
                    (incorporated by reference to Exhibit 10.40 filed to the
                    Company's Registration Statement on Form S-1 (File 33-93804)
                    declared effective on August 22, 1995).
</TABLE>
    

                                      II-5
<PAGE>   43

<TABLE>
<CAPTION>


        EXHIBIT
        NUMBER                                DESCRIPTION
   --------------   ----------------------------------------------------------------------------------------
          <S>       <C>
          10.23     Software License and Distribution Agreement between the
                    Company and Sprint International Communications Corporation
                    ("Sprint") effective July 27, 1990 with First Amendment
                    effective as of May 24, 1993 (incorporated by reference to
                    Exhibit 10.41 filed to the Company's Registration Statement
                    on Form S-1 (File 33-93804) declared effective on August 22,
                    1995).

          10.24     Reseller Agreement (now known as Service Management
                    Agreement) between the Company and Sprint effective July 27,
                    1990 with First Amendment effective as of May 1, 1991,
                    Second Amendment effective as of May 1, 1992, and Third
                    Amendment dated July 1, 1994 (incorporated by reference to
                    Exhibit 10.42 filed to the Company's Registration Statement
                    on Form S-1 (File 33-93804) declared effective on August 22,
                    1995).

          10.25     Form of Indemnification Agreement between the Company and
                    Directors (incorporated by reference to Exhibit 10.43 filed
                    to the Company's Registration Statement on Form S-1 (File
                    33-93804) declared effective on August 22, 1995).

          10.26     Harbinger Corporation 1996 Stock Option Plan (incorporated
                    by reference to Exhibit 10.48 to the Company's Annual Report
                    on Form 10-K for the year ended December 31, 1995).

          10.27     First Amendment to Harbinger Corporation 1996 Stock Option
                    Plan. (incorporated by reference to Exhibit 10.26 to the
                    Company's Annual Report on Form 10-K for the year ended
                    December 31, 1996).

          10.28     Amended and Restated Harbinger Corporation Employee Stock
                    Purchase Plan (incorporated by reference to Exhibit 10.49 to
                    the Company's Annual Report on Form 10-K for the year ended
                    December 31, 1995).

          10.29     First Amendment to Harbinger Corporation Employee Stock
                    Purchase Plan. (incorporated by reference to Exhibit 10.28
                    to the Company's Annual Report on Form 10-K for the year
                    ended December 31, 1996).

          10.30     First Amendment to Harbinger Corporation Amended and
                    Restated 1989 Stock Option Plan (incorporated by reference
                    to Exhibit 10.50 to the Company's Annual Report on Form 10-K
                    for the year ended December 31, 1995).

          10.31     Alliance Agreement dated July 21, 1995 between Systems
                    Software Associates, Inc. and the Company (incorporated by
                    reference to Exhibit 10.47 to the Company's Registration
                    Statement on Form S-1 (File No. 33-93804)).

          10.32     First Amendment to Alliance Agreement between System
                    Software Associates, Inc. and Harbinger Corporation
                    (incorporated by reference to Exhibit 10.51 to the Company's
                    Annual Report on Form 10-K for the year ended December 31,
                    1995).

          10.33     Employment Agreement between the Company and Mr. Theodore C.
                    Annis effective January 3, 1997 (incorporated by reference
                    to Exhibit 99.2 filed with the Company's Current Report on
                    Form 8-K/A dated March 17, 1997).




</TABLE>
                                      II-6

<PAGE>   44


<TABLE>
<CAPTION>
        EXHIBIT
        NUMBER                                DESCRIPTION
   --------------   ----------------------------------------------------------------------------------------
          <S>       <C>
          10.34     Employment Agreement between the Company and Ms. A. Gail
                    Jackson effective January 3, 1997 (incorporated by reference
                    to Exhibit 99.3 filed with the Company's Current Report on
                    Form 8-K/A dated March 17, 1997).

          23.1      Consents of KPMG Peat Marwick LLP.
   
          23.2      Consent of Arthur Andersen LLP.

          23.3      Consent of Ciulla, Smith & Dale, LLP.

          23.4      Consent of Moret Ernst & Young Accountants.

          23.5      Consent of KPMG Deutsche Treuhand-Gesellschaft AG.

          23.6      Consent of KPMG Accountants N.V.

          23.7      Consent of Ernst & Young LLP.

          23.8      Consent of Morris Manning & Martin, L.L.P. (included in
                    Exhibit 5.1).

          24.1      Power of Attorney (include at Page II-9 of this Registration
                    Statement).
</TABLE>

- -------
   
    
   
**  Previously filed.
    
+   The Company has received confidential treatment with respect to portions of
    these Exhibits.



ITEM 17.  UNDERTAKINGS.

         The undersigned Registrant hereby undertakes:

         (1) To file, during any period in which offers or sales are being made,
a post-effective amendment to this Registration Statement.

             (i)   To include in any prospectus required by Section 10(a)(3) of
the  Securities Act of 1933;

             (ii)  To reflect in the prospectus any facts or events arising
after the effective date of this Registration Statement (or the most recent
post-effective amendment thereof) which, individually or in the aggregate,
represent a fundamental change in the information set forth in this Registration
Statement. Notwithstanding the foregoing, any increase or decrease in volume of
securities offered (if the total dollar value of securities offered would not
exceed that which was registered) and any deviation from the low or high end of
the estimated maximum offering range may be reflected in the form of prospectus
filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the
changes in volume and price represent no more than a 20% change in the maximum
offering price set forth in the "Calculation of Registration Fee" table in the
effective registration statement;

             (iii) To include any material information with respect to the
plan of distribution not previously disclosed in this Registration Statement or
any material change to such information in this Registration Statement;



                                     11-7
<PAGE>   45

provided, however, that paragraphs (1)(i) and (1)(ii) do not apply if the
information required to be included in a post-effective amendment by those
paragraphs is contained in periodic reports filed by the Company pursuant to
Section 13 or Section 15(d) of the Securities Exchange Act of 1934, as amended
(the "Exchange Act") that are incorporated by reference in this Registration
Statement.

         (2) That, for the purpose of determining any liability under the
Securities Act of 1933, each such post-effective amendment shall be deemed to be
a new registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

         (3) To remove from registration by means of a post-effective amendment
any of the securities being registered which remain unsold at the termination of
the offering.

         (4) For purposes of determining any liability under the Securities Act
of 1933, each filing of the Registrant's Annual Report pursuant to Section 13(a)
or Section 15(d) of the Securities Exchange Act of 1934 (and, where applicable,
each filing of an employee benefit plan's annual report pursuant to Section
15(d) of the Securities Exchange Act of 1934) that is incorporated by reference
in the registration statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.




                                      II-8
<PAGE>   46



                                   SIGNATURES
   

         Pursuant to the requirements of the Securities Act of 1933, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-3 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly 
authorized, in the City of Atlanta, State of Georgia on the 28th day of July, 
1997.
    


                                    HARBINGER CORPORATION

                                    By: /s/ Joel G. Katz  
                                        ----------------------------------------
                                        Joel G. Katz, Chief Financial Officer




                                      II-9

<PAGE>   47





         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed below by the following persons in the
capacities and on the dates indicated.


   
<TABLE>
<CAPTION>

<S>                                 <C>                                                 <C> 

        *                           Chairman of the Board of Directors                  July 28, 1997
- ---------------------------
C. Tycho Howle


        *                           Chief Executive Officer                             July 28, 1997
- ---------------------------         and Director                 
David T. Leach                      (Principal Executive Officer)
                                                                 

        *                           President, Chief Operating Officer                  July 28, 1997
- ---------------------------         and Director 
James C. Davis                                   

        *                           Chief Financial Officer and Secretary               July 28, 1997
- ---------------------------         (Principal Financial Officer and Principal 
Joel G. Katz                        Accounting Officer)                        
                                                                               

        *                           Director                                            July 28, 1997
- ---------------------------
William D. Savoy


        *                           Director                                            July 28, 1997
- ---------------------------
William B. King


        *                           Director                                            July 28, 1997
- ---------------------------
Stuart L. Bell


        *                           Director                                            July 28, 1997
- ---------------------------
Benn R. Konsynski


        *                           Director                                            July 28, 1997
- ---------------------------
Klaus Neugebauer


        *                           Director                                            July 28, 1997
- ---------------------------
Ad Nederlof
</TABLE>
    


*By: /s/ Joel G. Katz
    -----------------------
     Joel G. Katz
     Attorney-in-Fact


                                     II-10
<PAGE>   48

                                  EXHIBIT INDEX

         The following exhibits are filed with or incorporated by reference into
this Registration Statement pursuant to Item 601 of Regulation S-K:

   
<TABLE>
<CAPTION>

       EXHIBIT                                                                              SEQUENTIAL PAGE
       NUMBER                                 DESCRIPTION                                         NUMBER
   --------------   -------------------------------------------------------------------------------------------------
          <S>       <C>                                                                             <C> 

          1.1       Form of Underwriting Agreement

          2.1       Share Purchase Agreement effective as of March 31, 1996                         N/A
                    among F.J. Nederlof B.V., H.W.I. Bol, Arthur Nederlof
                    B.V. (the "NTEX Shareholders") and the Company (incorporated
                    by reference to Exhibit 2(a) filed with the Company's
                    Current Report on Form 8-K dated April 18, 1996).

          2.2       Share Purchase Agreement effective as of March 31, 1996                         N/A
                    among Jakob Karszt, Helmut Grimm, Hans Rauh, Nikolai
                    Preis, Ulrich Rehn, Eugen Volbers, Jurgen M. Diet, Wolffried
                    Stucky and Jorg Blum (the "INOVIS Shareholders") and the
                    Company (incorporated by reference to Exhibit 2(a) filed
                    with the Company's Current Report on Form 8-K dated May 2,
                    1996).

          2.3       Debenture Purchase Agreement effective as of January 1, 1997                    N/A
                    between BellSouth Telecommunications, Inc. and the
                    Company (incorporated by reference to Exhibit 2.1 filed with
                    the Company's Current Report on Form 8-K dated January 15,
                    1997).

          2.4       Merger Agreement dated January 3, 1997 among SupplyTech,                        N/A
                    Inc., Harbinger Acquisition Corporation II and the
                    Company (incorporated by reference to Exhibit 2.1 filed with
                    the Company's Current Report on Form 8-K dated January 16,
                    1997).

          2.5       Agreement and Plan of Reorganization between and among                          N/A
                    Vulcan Ventures, Inc., AXA Equity & Law Life Assurance
                    Society, Ltd. (the "HNV Shareholders"), Harbinger N.V. and
                    the Company effective as of March 29, 1996 (incorporated by
                    reference to Exhibit 2(a) filed with the Company's Current
                    Report on Form 8-K dated May 3, 1996).

          3.1       Amended and Restated Articles of Incorporation of the                           N/A
                    Company (incorporated by reference to Exhibit 3.1 to the
                    Company's Registration Statement on Form S-1 (File 33-93804)
                    declared effective on August 22, 1995).

          3.2       Amended and Restated Bylaws of the Company (incorporated by                     N/A
                    reference to Exhibit 3.2 to the Company's Annual Report
                    on Form 10-K for the year ended December 31, 1996).

</TABLE>
    

                                     II-11
<PAGE>   49
   
<TABLE>
<CAPTION>


        EXHIBIT                                                                                   SEQUENTIAL PAGE
        NUMBER                                      DESCRIPTION                                       NUMBER
   ---------------  ---------------------------------------------------------------------------------------------------
          <S>       <C>                                                                                  <C>
          4.1       Provisions of the Amended and Restated Articles of                                   N/A
                    Incorporation and Amended and Restated Bylaws of the
                    Company defining rights of the holders of the Common Stock
                    (incorporated by reference to Exhibits 3.1 through 3.4 to
                    the Company's Registration Statement on Form S-1 (File No.
                    33-93804) declared effective on August 22, 1995).
     
          4.2       Specimen Stock Certificate (incorporated by reference to                             N/A
                    Exhibit 4.3 to the Company's Registration Statement on
                    Form S-1 (File 33-93804)).

          4.3       Form of Registration Rights Agreement effective March 31,                            N/A        
                    1996 between the Company and each of the NTEX
                    Shareholders (incorporated by reference to Exhibit 2(a)
                    filed with the Company's Current Report on Form 8-K dated
                    April 18, 1996). 

          4.4       Form of Registration Rights Agreement effective                                      N/A
                    March 29, 1996 between each of the Harbinger
                    N.V. Shareholders and the Company (incorporated by reference
                    to Exhibit 2(a) filed with the Company's Current Report on
                    Form 8-K dated May 3, 1996).

          4.5       Form of Warrant issued to former Harbinger N.V. Shareholders                         N/A
                    on July 18, 1996 (incorporated by reference to Exhibit
                    4.5 to the Company's Annual Report on Form 10-K for the year
                    ended December 31, 1996).

          4.6       Registration Rights Agreement among the former shareholders                          N/A
                    of SupplyTech, Inc. and the Company effective January 3,
                    1997 (incorporated by reference to Exhibit 4.1 filed with
                    the Company's Current Report on Form 8-K dated January 16,
                    1997).

          4.7       Form of Warrant issued to former INOVIS Shareholders on                              N/A
                    April 19, 1996 (incorporated by reference to Exhibit
                    2(a) filed with the Company's Current Report on Form 8-K
                    dated July 1, 1996).

          4.8       Form of Registration Rights Agreement effective March 31,                            N/A
                    1996 between each of the former INOVIS Shareholders and
                    the Company (incorporated by reference to Exhibit 2(a) filed
                    with the Company's Current Report on Form 8-K dated July 1,
                    1996).

          5.1**     Opinion of Morris, Manning & Martin, L.L.P. as to the                                N/A
                    legality of the securities being registered.

         10.1       Promissory Note for $10,000,000 payable by the Company to                            N/A
                    NationsBank of Georgia, N.A. dated April 16, 1997
                    (incorporated by reference to Exhibit 10.1 filed to the
                    Company's Registration Statement on Form S-3 (File No.
                    333-30501) declared effective on July 3, 1997).
</TABLE>
    

                                     II-12

<PAGE>   50
<TABLE>
<CAPTION>


        EXHIBIT                                                                                    SEQUENTIAL PAGE
        NUMBER                                DESCRIPTION                                                NUMBER
   ---------------- -------------------------------------------------------------------------------------------------
          <S>       <C>                                                                                  <C>    

          10.2      Loan Agreement between the Company and NationsBank of                                N/A
                    Georgia, N.A. dated as of August 15, 1994 with First
                    Amendment dated as of May 2, 1995 (incorporated by reference
                    to Exhibit 10.13 filed to the Company's Registration
                    Statement on Form S-1 (File 33-93804) declared effective on
                    August 22, 1995).

          10.3      Second Amendment to Loan Agreement between the Company and                           N/A
                    NationsBank, National Association (South) dated April
                    16, 1997 (incorporated by reference to Exhibit 10.3 filed to
                    the Company's Registration Statement on Form S-3 (File No.
                    333-30501) declared effective on July 3, 1997).

          10.4      Employment Agreement between the Company and Mr. James M.                            N/A
                    Travers effective as of February 1, 1995 with letter
                    from the Company to Mr. Travers dated December 27, 1994
                    (incorporated by reference to Exhibit 10.14 filed to the
                    Company's Registration Statement on Form S-1 (File 33-93804)
                    declared effective on August 22, 1995).

          10.5**    Employment Agreement between the Company and Mr. James C.                            N/A
                    Davis effective as of July 1, 1997.

          10.6      Assignment of Invention and Patents Thereon (Patent                                  N/A
                    5,367,664) by Texas Instruments, Incorporated ( "TI ")                 
                    to the Company dated January 12, 1995 as recorded with
                    United States Patent and Trademark Office on March 13, 1995
                    (incorporated by reference to Exhibit 10.16 filed to the
                    Company's Registration Statement on Form S-1 (File 33-93804)
                    declared effective on August 22, 1995).

          10.7      U.S. Patent 5,367,664 issued November 22, 1994 (incorporated                         N/A
                    by reference to Exhibit 10.17 filed to the Company's
                    Registration Statement on Form S-1 (File 33-93804) declared
                    effective on August 22, 1995).

          10.8      Assignment of Invention and Patents Thereon (Application                             N/A
                    07/502,955) by TI to the Company dated January 12, 1995 as
                    recorded with United States Patent and Trademark Office on
                    March 13, 1995 (incorporated by reference to Exhibit 10.18
                    filed to the Company's Registration Statement on Form S-1
                    (File 33-93804) declared effective on August 22, 1995).

          10.9      Asset Purchase Agreement between the Company and TI dated as                         N/A 
                    of December 31, 1994 (incorporated by reference to
                    Exhibit 10.19 filed to the Company's Registration Statement
                    on Form S-1 (File 33-93804) declared effective on August 22,
                    1995).
</TABLE>


                                     II-13
<PAGE>   51
g
<TABLE>
<CAPTION>


        EXHIBIT                                                                                     SEQUENTIAL PAGE
        NUMBER                                DESCRIPTION                                                NUMBER
   ---------------  -------------------------------------------------------------------------------------------------
          <S>       <C>                                                                                  <C>

          10.10     Employment Agreement between the Company and Mr. David A.                            N/A
                    Meeker effective as of December 21, 1994 (incorporated
                    by reference to Exhibit 10.21 filed to the Company's
                    Registration Statement on Form S-1 (File 33-93804) declared
                    effective on August 22, 1995).

          10.11     401(k) Profit Sharing Plan amended and restated effective as                         N/A
                    of September 1, 1994; original effective date October 1,
                    1991 (incorporated by reference to Exhibit 10.24 filed to
                    the Company's Registration Statement on Form S-1 (File
                    33-93804) declared effective on August 22, 1995).

          10.12     Employment Agreement between the Company and Mr. C. Tycho                            N/A
                    Howle effective as of March 4, 1997 (incorporated by
                    reference to Exhibit 10.11 to the Company's Annual Report on
                    Form 10-K for the year ended December 31, 1996).

          10.13**   First Amendment to Employment Agreement between the Company                          N/A
                    and Mr. C. Tycho Howle effective as of July 1, 1997.

          10.14     Employment Agreement between the Company and Mr. Joel G.                             N/A  
                    Katz effective as of March 7, 1994 (incorporated by
                    reference to Exhibit 10.26 filed to the Company's
                    Registration Statement on Form S-1 (File 33-93804) declared
                    effective on August 22, 1995).

          10.15**   Employment Agreement between the Company and Mr. David T.                            N/A
                    Leach effective as of July 1, 1997.

          10.16+    License and Service Agreement between the Company and Bank                           N/A  
                    of America National Trust and Savings Association dated
                    as of February 18, 1994 (incorporated by reference to
                    Exhibit 10.29 filed to the Company's Registration Statement
                    on Form S-1 (File 33-93804) declared effective on August 22,
                    1995).

          10.17     Amended and Restated 1993 Stock Option Plan for Nonemployee                          N/A
                    Directors effective as of August 11, 1993 (incorporated
                    by reference to Exhibit 10.33 filed to the Company's
                    Registration Statement on Form S-1 (File 33-93804) declared
                    effective on August 22, 1995).

          10.18     Third Amendment to Amended and Restated 1993 Stock Option                            N/A
                    Plan for Nonemployee Directors (incorporated by
                    reference to Exhibit 10.17 to the Company's Annual Report on
                    Form 10-K for the year ended December 31, 1996).


</TABLE>

                                     II-14
<PAGE>   52


<TABLE>
<CAPTION>

       EXHIBIT                                                                                  SEQUENTIAL PAGE
        NUMBER                                DESCRIPTION                                            NUMBER
   ---------------  -----------------------------------------------------------------------------------------------
          <S>       <C>                                                                             <C>

          10.19     Co-Marketing Agreement between the Company and Sprint                           N/A
                    Communications Company Limited Partnership of Delaware made
                    as of August 9, 1993 (incorporated by reference to Exhibit
                    10.34 filed to the Company's Registration Statement on Form
                    S-1 (File 33-93804) declared effective on August 22, 1995).

          10.20     Lease between the Company and Lenox Park Development 1 L.P.                     N/A
                    for office located at 1055 Lenox Park Boulevard,
                    Atlanta, Georgia dated July 16, 1992 with First Amendment
                    dated July 22, 1993 and Second Amendment dated December 27,
                    1993 (incorporated by reference to Exhibit 10.38 filed to
                    the Company's Registration Statement on Form S-1 (File
                    33-93804) declared effective on August 22, 1995).

          10.21     Amended and Restated 1989 Stock Option Plan effective as of                     N/A
                    April 15, 1992 (incorporated by reference to Exhibit
                    10.39 filed to the Company's Registration Statement on Form
                    S-1 (File 33-93804) declared effective on August 22, 1995).

          10.22+    Harbinger Business Financial Management System License                          N/A
                    Agreement between the Company as assignee of Harbinger
                    Computer Services, Inc. and Barnett Banks, Inc. dated
                    November 18, 1991 with amendment dated May 21, 1992
                    (incorporated by reference to Exhibit 10.40 filed to the
                    Company's Registration Statement on Form S-1 (File 33-93804)
                    declared effective on August 22, 1995).

          10.23     Software License and Distribution Agreement between the                         N/A
                    Company and Sprint International Communications
                    Corporation ("Sprint") effective July 27, 1990 with First
                    Amendment effective as of May 24, 1993 (incorporated by
                    reference to Exhibit 10.41 filed to the Company's
                    Registration Statement on Form S-1 (File 33-93804) declared
                    effective on August 22, 1995).

          10.24     Reseller Agreement (now known as Service Management                             N/A  
                    Agreement)between the Company and Sprint effective July
                    27, 1990 with First Amendment effective as of May 1, 1991,
                    Second Amendment effective as of May 1, 1992, and Third
                    Amendment dated July 1, 1994 (incorporated by reference to
                    Exhibit 10.42 filed to the Company's Registration Statement
                    on Form S-1 (File 33-93804) declared effective on August 22,
                    1995).

          10.25     Form of Indemnification Agreement between the Company and                       N/A
                    Directors (incorporated by reference to Exhibit 10.43
                    filed to the Company's Registration Statement on Form S-1
                    (File 33-93804) declared effective on August 22, 1995).

</TABLE>


                                   II-15
<PAGE>   53

<TABLE>
<CAPTION>


        EXHIBIT                                                                                  SEQUENTIAL PAGE
        NUMBER                                DESCRIPTION                                              NUMBER
   ---------------  ----------------------------------------------------------------------------------------------------
          <S>       <C>                                                                                  <C>
  
          10.26     Harbinger Corporation 1996 Stock Option Plan (incorporated                           N/A
                    by reference to Exhibit 10.48 to the Company's Annual
                    Report on Form 10-K for the year ended December 31, 1995).

          10.27     First Amendment to Harbinger Corporation 1996 Stock Option                           N/A  
                    Plan (incorporated by reference to Exhibit 10.26 to the
                    Company's Annual Report on Form 10-K for the year ended
                    December 31, 1996).

          10.28     Amended and Restated Harbinger Corporation Employee Stock                            N/A
                    Purchase Plan (incorporated by reference to Exhibit
                    10.49 to the Company's Annual Report on Form 10-K for the
                    year ended December 31, 1995).

          10.29     First Amendment to Harbinger Corporation Employee Stock                              N/A
                    Purchase Plan. (incorporated by reference to Exhibit
                    10.28 to the Company's Annual Report on Form 10-K for the
                    year ended December 31, 1996).

          10.30     First Amendment to Harbinger Corporation Amended and                                 N/A
                    Restated 1989 Stock Option Plan (incorporated by
                    reference to Exhibit 10.50 to the Company's Annual Report on
                    Form 10-K for the year ended December 31, 1995).

          10.31     Alliance Agreement dated July 21, 1995 between Systems                               N/A
                    Software Associates, Inc. and the Company (incorporated
                    by reference to Exhibit 10.47 to the Company's Registration
                    Statement on Form S-1 (File No. 33-93804)).

          10.32     First Amendment to Alliance Agreement between System                                 N/A
                    Software Associates, Inc. and Harbinger Corporation
                    (incorporated by reference to Exhibit 10.51 to the Company's
                    Annual Report on Form 10-K for the year ended December 31,
                    1995).

          10.33     Employment Agreement between the Company and Mr. Theodore C.                         N/A
                    Annis effective January 3, 1997 (incorporated by
                    reference to Exhibit 99.2 filed with the Company's Current
                    Report on Form 8-K/A dated March 17, 1997).

          10.34     Employment Agreement between the Company and Ms. A. Gail                             N/A
                    Jackson effective January 3, 1997 (incorporated by
                    reference to Exhibit 99.3 filed with the Company's Current
                    Report on Form 8-K/A dated March 17, 1997).

          23.1      Consents of KPMG Peat Marwick LLP.

          23.2      Consent of Arthur Andersen LLP.

          23.3      Consent of Ciulla, Smith & Dale, LLP.
</TABLE>

                                    II-16

<PAGE>   54

<TABLE>
<CAPTION>

        EXHIBIT                                                                                  SEQUENTIAL PAGE
        NUMBER                                DESCRIPTION                                             NUMBER
   ---------------  --------------------------------------------------------------------------------------------------
          <S>       <C>                                                                                  <C>
          23.4      Consent of Moret Ernst & Young Accountants.

          23.5      Consent of KPMG Deutsche Treuhand-Gesellschaft AG.

          23.6      Consent of KPMG Accountants N.V.

          23.7      Consent of Ernst & Young LLP.

          23.8      Consent of Morris Manning & Martin, L.L.P. (included in                              N/A
                    Exhibit 5.1). 

          24.1      Power of Attorney (include at Page II-9 of this Registration                         N/A
                    Statement). 
</TABLE>


- ----------- 
   
    
**Previously filed.
+ The Company has received confidential treatment with respect to portions of 
  these Exhibits.
            


                                     II-17


<PAGE>   1
                                                                     EXHIBIT 1.1


                                2,900,000 Shares


                             HARBINGER CORPORATION


                                  Common Stock

                          (Par Value $.0001 per share)



                             UNDERWRITING AGREEMENT



                                                                   July __, 1997

ALEX. BROWN & SONS INCORPORATED
ROBERTSON, STEPHENS & COMPANY LLC
THE ROBINSON-HUMPHREY COMPANY, INC.
INTERSTATE JOHNSON LANE CORPORATION
As the Representatives of the Several Underwriters
c/o ALEX. BROWN & SONS INCORPORATED
1 South Street
Baltimore, Maryland 21202

Ladies and Gentlemen:

     Harbinger Corporation, a Georgia corporation (the "Company") and certain
shareholders of the Company named in Schedule II hereto (the "Selling
Shareholders"), propose to sell to the several underwriters (the
"Underwriters") named in Schedule I hereto for whom you are acting as
representatives (the "Representatives") an aggregate of 2,900,000 shares of the
Company's Common Stock,  par value $.0001 per share (the "Firm Shares") of
which 1,800,000 shares will be sold by the Company and 1,100,000 shares will be
sold by the Selling Shareholders.  The respective amounts of the Firm Shares to
be so purchased by the several Underwriters are set forth opposite their names
in Schedule I hereto.  Certain Selling Shareholders named in Schedule II and
the Company also propose to sell at the Underwriters' option an aggregate of up
to 435,000 additional shares of the Company's Common Stock (the "Option
Shares") as set forth on Schedule II.  The Selling Shareholders have executed 
Custody Agreements (the "Custody Agreement") and certain of them have executed 
Powers of Attorney, the forms of which have been previously delivered to you, 
pursuant to which the Selling Shareholders have 

                                     - 1 -

<PAGE>   2

placed their respective Selling Shareholder Shares in custody with the Company 
and agreed to take certain other actions with respect thereto and hereto.

     As the Representatives of the Underwriters, you have advised the Company
and the Selling Shareholders (a) that you are authorized to enter into this
Agreement on behalf of the several Underwriters, and (b) that the Underwriters
are willing, acting severally and not jointly, to purchase the numbers of Firm
Shares set forth opposite their respective names in Schedule I, plus their pro
rata portion of the Option Shares if you elect to exercise the over-allotment
option in whole or in part.  The Firm Shares and the Option Shares (to the
extent the aforementioned option is exercised) are herein collectively called
the "Shares."

     In consideration of the mutual agreements contained herein and of the
interests of the parties in the transactions contemplated hereby, the parties
hereto agree as follows:

     1.   Representations and Warranties of the Company and the Selling
          Shareholders.

     (a)  The Company represents and warrants as follows:

           (i) A registration statement on Form S-3 (File No. 333-_________)
      with respect to the Shares has been carefully prepared by the Company in
      conformity with the requirements of the Securities Act of 1933, as
      amended (the "Act"), and the Rules and Regulations (the "Rules and
      Regulations") of the Securities and Exchange Commission (the
      "Commission") thereunder and has been filed with the Commission under
      the Act.  The Company has complied with the conditions for the use of
      Form S-3.  Copies of such registration statement, including any
      amendments thereto, the preliminary prospectuses contained therein and
      the exhibits, financial statements and schedules, as finally amended and
      revised, have heretofore been delivered by the Company to you.  Such
      registration statement, together with any registration statement filed
      by the Company pursuant to Rule 462(b) of the Act, herein referred to as
      the "Registration Statement," which shall be deemed to include all
      information omitted therefrom in reliance upon Rule 430A and contained
      in the Prospectus referred to below, has been declared effective by the
      Commission under the Act and no post-effective amendment to the
      Registration Statement has been filed as of the date of this Agreement.
      "Prospectus" means (i) the form of prospectus first filed by the Company
      with the Commission pursuant to its Rule 424(b) or (ii) the last
      preliminary prospectus included in the Registration Statement filed
      prior to the time it becomes effective or filed pursuant to Rule 424(a)
      under the Act that is delivered by the Company to the Underwriters for
      delivery to purchasers of the Shares, together with any term sheet or
      abbreviated term sheet filed with the Commission pursuant to Rule
      424(b)(7) under the Act.  Each preliminary prospectus included in the
      Registration Statement prior to the time it becomes 

                                     - 2 -
<PAGE>   3

      effective is herein referred to as a "Preliminary Prospectus." Except as 
      specifically set forth herein, (i) any reference herein to any 
      Preliminary Prospectus or the Prospectus, as the case may be, and (ii)
      in the case of any reference  herein to any Prospectus, shall be deemed
      to include any documents incorporated by reference therein, and any
      supplements or amendments thereto, filed with the Commission after the
      date of filing of the Prospectus under Rules 424(b) and 430A, and prior
      to the termination of the offering of the Shares by the Underwriters.

           (ii) The Company has been duly organized and is validly existing as
      a corporation in good standing under the laws of the State of Georgia,
      with corporate power and authority to own or lease its properties and
      conduct its business as described in the Registration Statement; each of
      the subsidiaries of the Company listed on Schedule III hereto
      (collectively, the "Subsidiaries") has been duly organized and is
      validly existing as a corporation or limited liability company, as the
      case may be, in good standing under the laws of the jurisdiction of its
      organization, with power and authority to own or lease their respective
      properties and conduct their respective businesses as described in the
      Registration Statement.  The Company and each of the Subsidiaries are
      duly qualified to transact business in all jurisdictions in which the
      conduct of their business requires such qualification except where the
      failure to so qualify would not, in the aggregate, have a material
      adverse effect on the Company or any of its Subsidiaries; the
      outstanding capital shares of each of the Subsidiaries have been duly
      authorized and validly issued, are fully paid and non-assessable and the
      outstanding capital shares of each of the Subsidiaries owned by the
      Company as described in the Registration Statement are owned free and
      clear of all liens, encumbrances and security interests except as
      described the Registration Statement and no options, warrants or other
      rights to purchase, agreements or other obligations to issue or other
      rights to convert any obligations into shares of capital stock or
      ownership interests in the Subsidiaries are outstanding.  Except for its
      investment in securities of the Subsidiaries as described in the
      Registration Statement, the Company has no equity or other interest in,
      or right to acquire, an equity or other interest in, any corporation,
      partnership, trust or other entity.

           (iii) The authorized shares of Common Stock of the Company have
      been duly authorized.  The outstanding shares of Common Stock of the
      Company, including all shares to be sold by the Selling Shareholders,
      have been duly authorized and validly issued and are fully paid and
      non-assessable; the Shares to be issued and sold by the Company have
      been duly authorized and when issued and paid for as contemplated herein
      will be validly issued, fully-paid and non-assessable; and no preemptive
      rights of stockholders exist with respect to any of the Shares or the
      issue and sale thereof.  Neither the filing of the Registration
      Statement nor the offering or sale of the Shares as contemplated by this 

                                     - 3 -

<PAGE>   4

      Agreement gives rise to any rights, other than those which have been 
      waived or satisfied, for or relating to the registration of any shares of 
      Common Stock.

           (iv) This Agreement has been duly authorized, executed and
      delivered by the Company and is a legal, valid and binding obligation of
      the Company enforceable against the Company in accordance with its
      terms.

           (v) The information set forth under the caption "Capitalization" in
      the Prospectus is true and correct. The Shares conform with the
      statements concerning them in the Registration Statement.

           (vi) The Commission has not issued an order preventing or
      suspending the use of any Prospectus or Preliminary Prospectus relating
      to the proposed offering of the Shares nor instituted proceedings for
      that purpose.  The Registration Statement contains and the Prospectus
      and any amendments or supplements thereto will contain all statements
      which are required to be stated therein by, and in all respects conform
      or will conform, as the case may be, to the requirements of, the Act and
      the Rules and Regulations.  The documents incorporated by reference in
      the Prospectus, at the time they were filed with the Commission
      conformed in all material respects to the requirements of the Securities
      Exchange Act of 1934 or the Act, as applicable, and the Rules and
      Regulations of the Commission thereunder.  Neither the Registration
      Statement nor any amendment thereto, and neither the Prospectus nor any
      supplement thereto, including any documents incorporated by reference
      therein, contains or will contain, as the case may be, any untrue
      statement of a material fact or omits or will omit to state any material
      fact required to be stated therein or necessary to make the statements
      therein, in the light of the circumstances under which they were made,
      not misleading; provided, however, that the Company makes no
      representations or warranties as to information contained in or omitted
      from the Registration Statement or the Prospectus, or any such amendment
      or supplement, or any documents incorporated by reference therein, in
      reliance upon, and in conformity with, written information furnished to
      the Company by or on behalf of any Underwriter through the
      Representatives, specifically for use in the preparation thereof.

           (vii) The financial statements of the Company, together with
      related notes and schedules as set forth and incorporated by reference
      in the Registration Statement, present fairly the financial position and
      the results of operations of the Company, at the indicated dates and for
      the indicated periods.  Such financial statements have been prepared in
      accordance with generally accepted principles of accounting,
      consistently applied throughout the periods involved, and all
      adjustments necessary for a fair presentation of results for such
      periods have been made.  The summary financial and statistical data
      included in the Registration 

                                     - 4 -

<PAGE>   5

      Statement present fairly the information shown therein and have been 
      compiled on a basis consistent with the financial statements presented 
      therein.

           (viii) The statements of operations of EDI, a former business unit
      of Texas Instruments Incorporated ("EDI"), together with related notes
      and schedules as set forth in the Registration Statement, present fairly
      the results of operations of EDI for the indicated periods.  Such
      statements of operations have been prepared in accordance with generally
      accepted principles of accounting, consistently applied throughout the
      periods involved, and all adjustments necessary for a fair presentation
      of results for such periods have been made.  Supply Tech

           (ix) The Pro Forma Financial Statements of the Company incorporated
      by reference in the Prospectus and in the Registration Statement have
      been prepared in conformity with the requirements of Article 11 of
      Regulation S-X and present fairly the information shown therein.

           (x) There is no action or proceeding pending or, to the knowledge
      of the Company, threatened against the Company or any of the
      Subsidiaries before any court or administrative agency or by any
      regulatory authority which might result in any material adverse change
      in the business or financial condition of the Company, except as set
      forth in the Registration Statement.

           (xi) The Company and the Subsidiaries have good and marketable
      title to all of the properties and assets reflected in the financial
      statements herein above described (or as described in the Registration
      Statement), subject to no lien, mortgage, pledge, charge or encumbrance
      of any kind except those reflected in such financial statements (or as
      described in the Registration Statement) or which are not material in
      amount.  The Company and the Subsidiaries occupy their leased properties
      under valid and binding leases conforming to the description thereof set
      forth in the Registration Statement.

           (xii) The Company and the Subsidiaries have filed all Federal,
      State and foreign income tax returns which have been required to be
      filed and have paid all taxes indicated by said returns and all
      assessments received by them or any of them to the extent that such
      taxes have become due and are not being contested in good faith.

           (xiii) Since the respective dates as of which information is given
      in the Registration Statement, as it may be amended or supplemented,
      there has not been any material adverse change or any development
      involving a prospective material adverse change in or affecting the
      earnings, business, management, assets, rights, operations, condition
      (financial or otherwise) or business prospects of the Company and its 
      Subsidiaries (taken as a whole), whether or not occurring in the ordinary
      course of business, and there has not been any material transaction 
      entered into by the Company or the Subsidiaries, other than transactions 
      in the 

                                     - 5 -

<PAGE>   6

      ordinary course of business and changes and transactions contemplated by 
      the Registration Statement, as it may be amended or supplemented.  None 
      of the Company or the Subsidiaries have any material contingent 
      obligations which are not disclosed in the Registration Statement, as it 
      may be amended or supplemented.

           (xiv) Neither the Company nor any of the Subsidiaries is, nor with
      the giving of notice, lapse of time or both, will be, in default under
      their respective Articles of Incorporation or Bylaws (or in the case of
      HNS, its Articles of Organization or its Operating Agreement) or under
      any agreement, lease, contract, indenture or other instrument or
      obligation to which it is a party or by which it or any of its
      properties is bound and which default is of material significance in
      respect of the business or financial condition of the Company and the
      Subsidiaries taken as a whole.  The execution and delivery of this
      Agreement and the consummation of the transactions herein contemplated
      and the fulfillment of the terms hereof will not conflict with or result
      in a breach of any of the terms or provisions of, or constitute a
      default under, any indenture, mortgage, deed of trust or other agreement
      or instrument to which the Company or any Subsidiary is a party, or of
      the Articles of Incorporation or Bylaws of the Company or any order,
      rule or regulation applicable to the Company or the Subsidiaries of any
      court or of any regulatory body or administrative agency or other
      governmental body having jurisdiction.

           (xv) Each approval, consent, order, authorization, designation,
      declaration or filing by or with any regulatory, administrative or other
      governmental body necessary in connection with the execution and
      delivery by the Company of this Agreement and the consummation of the
      transactions herein contemplated (except such additional steps as may be
      required by the National Association of Securities Dealers, Inc. (the
      "NASD") or may be necessary to qualify the Shares for public offering by
      the Underwriters under State securities or Blue Sky laws) has been
      obtained or made and is in full force and effect.

           (xvi) The Company and each of the Subsidiaries hold all material
      licenses, certificates and permits from governmental authorities which
      are necessary to the conduct of its business; and neither the Company
      nor any of the Subsidiaries has reason to believe that it has, and has
      not received notice of any claim that it has, infringed any patents,
      patent rights, trade names, trademarks or copyrights, which infringement
      if successfully prosecuted, would have a material adverse effect on the
      business or financial condition of the Company.

           (xvii) KPMG Peat Marwick LLP, Arthur Andersen LLP, Ernst & Young 
      LLP, Ciulla, Smith & Dale, LLP, Moret Ernst & Young Accountants, KPMG


                                     - 6 -




<PAGE>   7





      Deutsche TreuhandGesellschaft AG and KPMG Accountants N.V., who have
      certified certain of the financial statements incorporated by reference
      in the Registration Statement and the Prospectus, are independent public
      accountants as required by the Act and the Rules and Regulations.

           (xviii) Neither the Company, nor to the Company's knowledge, any of
      the Subsidiaries, has taken or may take, directly or indirectly, any
      action designed to cause or result in, or which has constituted or which
      might reasonably be expected to constitute, the stabilization or
      manipulation of the price of the shares of Common Stock to facilitate
      the sale or resale of the Shares. The Company acknowledges that the
      Underwriters may engage in passive market making transactions in the
      Shares on The NYSE in accordance (and in compliance) with Regulation M
      under the Exchange Act.

           (xix) Neither the Company nor any Subsidiary has ever been, is now,
      and immediately after the sale of the Shares under this Agreement will
      be, an "investment company" within the meaning of the Investment Company
      Act of 1940, as amended.

     (b) Each Selling Shareholder severally and not jointly represents and
warrants to the Underwriters as follows:

           (i) Such Selling Shareholder now has and at the Closing Date or the
      Option Closing Date, as the case may be (as such dates are hereinafter
      defined), will have, good and marketable title to the Firm Shares or the
      Option Shares to be sold by such Selling Shareholder, as applicable, free
      of any liens, encumbrances, equities and claims, and full right, power
      and authority to effect the sale and delivery of such Firm Shares or
      Option Shares; and upon the delivery of and payment for such Firm Shares
      and Option Shares pursuant to this Agreement, the Underwriters will
      acquire good and marketable title thereto, free of any liens,
      encumbrances, security interests, rights, subscriptions, warrants, calls,
      preemptive rights, options or other agreements of any kind.

           (ii) Such Selling Shareholder has full right, power and authority to
      execute and deliver this Agreement, the Custodian Agreement and the Power
      of Attorney referred to below, and to perform its obligations under such
      agreements.  The consummation by such Selling Shareholder of the
      transactions herein contemplated and the fulfillment by such Selling
      Shareholder of the terms hereof will not (A) require any consent,
      approval, authorization or other order of any court, regulatory body,
      administrative agency or other governmental body (except as may be
      required under the Act, state securities laws or Blue Sky Laws) or (ii)
      result in a breach of any of the terms and provisions of, or constitute 
      a default under, any indenture, mortgage, deed of trust or other 
      agreement or instrument to which such Selling Shareholder is a party, or 
      of any order, rule or regulation 

                                     - 7 -

<PAGE>   8

      applicable to such Selling Shareholder of any court or of any regulatory 
      body or administrative agency or other governmental body having 
      jurisdiction.

           (iii) Such Selling Shareholder has not taken and will not take,
      directly or indirectly, any action designed to, or which has constituted,
      or which might reasonably be expected to cause or result in stabilization
      or manipulation of the price of the Common Stock of the Company.

           (iv) Such Selling Shareholder has executed and delivered this
      Agreement and the Custody Agreement, and in connection herewith, such
      Selling Shareholder further represents, warrants and agrees that such
      Selling Shareholder has deposited with ____________, pursuant to the
      Custody Agreement, the certificates in negotiable form representing such
      Selling Shareholder Shares for the purpose of further delivery pursuant
      to this Agreement; and the form of the Custody Agreement has been
      previously delivered to you.

           (v) No offering, sale or other disposition of any Common Stock of
      the Company will be made for a period of 90 days after the date of this
      Agreement, directly or indirectly, by such Seller otherwise than
      hereunder or with the prior written consent of the Underwriters.

           (vi) The Power of Attorney appointing certain individuals as such
      Selling Shareholder's attorney-in-fact to the extent set forth therein
      and in the Custodian Agreement (as defined in Section 2) have been duly
      executed and delivered by such Selling Shareholder and are the valid and
      binding agreements of such Selling Shareholder.

           (viii) To the best knowledge and without having undertaken to
      determine independently the accuracy or completeness of either the
      representations and warranties of the Company contained herein or the
      information contained in the Registration Statement, such Selling
      Shareholder has no reason to believe that the representations and
      warranties of the Company contained in this Section 1 are not true and
      correct, and has no knowledge of any material fact, condition or
      information not disclosed in the Registration Statement which has
      adversely affected or may adversely affect the business of the Company or
      any Subsidiary; and the sale of the Firm Shares by such Selling
      Shareholder pursuant hereto is not prompted by any information concerning
      the Company or any Subsidiary which is not set forth in the Registration
      Statement.  The information pertaining to such Selling Shareholder under
      the caption "Principal and Selling Shareholders" in the Prospectus is
      complete and accurate in all material respects and does not contain any 
      untrue statement of a material fact or omit to state any material fact
      required to be stated therein or necessary to make the statements therein
      not misleading.



                                     - 8 -


<PAGE>   9


     2. Purchase, Sale and Delivery of the Firm Shares.

     (a) On the basis of the representations, warranties and covenants herein
contained, and subject to the conditions herein set forth, the Company and the
Selling Shareholders agree to sell to the Underwriters and each Underwriter
agrees, severally and not jointly, to purchase, at a price of $____ per share,
the number of Firm Shares set forth opposite the name of each Underwriter in
Schedule I hereof, subject to adjustments in accordance with Section 9 hereof.
The number of Firm Shares to be purchased by each Underwriter from each Seller
shall be as nearly as practicable in the same proportion to the total number of
Firm Shares being sold by each Seller as the number of Firm Shares being
purchased by each Underwriter bears to the total number of Firm Shares to be
sold hereunder.  The obligations of the Company and the Selling Shareholders
shall be several and not joint.

     (b) Certificates in negotiable form for the total number of the Shares to
be sold hereunder by the Selling Shareholders have been placed in custody with
the ___________ (the "Custodian") pursuant to the Custodian Agreement executed
by each Selling Shareholder for delivery of all Shares to be sold hereunder by
the Selling Shareholders.  Each Selling Shareholder specifically agrees that
the Firm Shares represented by the certificates held in custody for such
Selling Shareholder under the Custody Agreement are subject to the interest of
the Underwriters hereunder, and that the arrangements made by such Selling
Shareholder for such custody are to that extent irrevocable, and that the
obligations of such Selling Shareholder hereunder shall not be terminable by
any act or deed of the Selling Shareholder (or by any other person, firm or
corporation, including the Company, the Custodian or the Underwriters) or by
operation of law or by the occurrence of any other event or events, except as
set forth in the Custody Agreement. If any such event should occur prior to the
delivery to the Underwriters of the Firm Shares hereunder, certificates for the
Firm Shares shall be delivered by the Custodian in accordance with the terms
and conditions of this Agreement as if such event had not occurred. The
Custodian is authorized to receive and acknowledge receipt of the proceeds of
the sale of the Selling Shareholder Shares held by it against the delivery of
such Shares.  The Attorneys or either of them are authorized to receive and
acknowledge receipt of the proceeds of sale of the Shares held by it against
delivery of such Shares.

     (c) Payment for the Firm Shares to be sold hereunder is to be made by wire
transfer of immediately available funds to the order of the Company for the
shares to be sold by it and to the order of the Custodian for the shares to be
sold by the Selling Shareholders, in each case against delivery of certificates
therefor to the Underwriters.  Such payment and delivery are to be made at the 
offices of Alex. Brown & Sons Incorporated, 1 South Street, Baltimore, 
Maryland, at 10:00 A.M., Baltimore time, on the third business day after the
date of this Agreement or at such other time and date not later than three 
business days thereafter as you and the Company shall agree upon, such time and
date being herein referred to as the "Closing Date."  (As used herein, 
"business day" 

                                     - 9 -
<PAGE>   10

means a day on which the New York Stock Exchange is open for trading and on 
which banks in New York are open for business and are not permitted by law or 
executive order to be closed.)  The certificates for the Firm Shares will be 
delivered in such denominations and in such registrations as the 
Representatives of the Underwriters request in writing not later than the 
second full business day prior to the Closing Date, and will be made available 
for inspection by the Underwriters at least one business day prior to the 
Closing Date.

     (d) In addition, on the basis of the representations and warranties herein
contained and subject to the terms and conditions herein set forth, the Company
and the Selling Shareholders listed on Schedule II hereto hereby grant an
option to the Underwriters to purchase the Option Shares at the price per share
as set forth in the first paragraph of this Section 2.  The maximum number of
Option Shares to be sold by the Company and the Selling Shareholders is set
forth opposite their respective names on Schedule II hereto.  The option
granted hereby may be exercised in whole or in part but only once and at any
time upon written notice given within 30 days after the date of this Agreement,
by you, the Underwriters, to the Company setting forth the number of Option
Shares as to which the several Underwriters are exercising the option, the
names and denominations in which the Option Shares are to be registered and the
time and date at which such certificates are to be delivered.  If the option
granted hereby is exercised in part, the respective number of Option Shares to
be sold by the Company and each of the Option Selling Shareholders listed in
Schedule II hereto shall be determined on a pro rata basis in accordance with
the percentages set forth opposite their names on Schedule II hereto, adjusted
by you in such manner as to avoid fractional shares.  The time and date at
which certificates for Option Shares are to be delivered shall be determined by
the Underwriters but shall not be earlier than three nor later than 10 full
business days after the exercise of such option, nor in any event prior to the
Closing Date (such time and date being herein referred to as the "Option
Closing Date").  If the date of exercise of the option is three or more days
before the Closing Date, the notice of exercise shall set the Closing Date as
the Option Closing Date.  The number of Option Shares to be purchased by each
Underwriter shall be in the same proportion to the total number of Option
Shares being purchased as the number of Firm Shares being purchased by such
Underwriter bears to the total number of Firm Shares, adjusted by you in such
manner as to avoid fractional shares.  The option with respect to the Option
Shares granted hereunder may be exercised only to cover over-allotments in the
sale of the Firm Shares by the Underwriters.  You, as Representatives of the
Underwriters, may cancel such option at any time prior to its expiration by
giving written notice of such cancellation to the Company.  To the extent, if
any, that the option is exercised, payment for the Option Shares shall be made
on the Option Closing Date by wire transfer of immediately available funds to 
the order of "___________, Custodian for Harbinger Selling Shareholders" for 
the Option Shares to be sold by the Selling Shareholders against delivery of 
certificates therefor at the offices of Alex. Brown & Sons Incorporated, 1 
South Street, Baltimore, Maryland.


                                     - 10 -
<PAGE>   11


     3. Offering by the Underwriters.  It is understood that the Underwriters
are to make a public offering of the Firm Shares as soon as the Representatives
deem it advisable to do so.  The Firm Shares are to be initially offered to the
public at the initial public offering price and on the selling terms set forth
in the Prospectus.  The Representatives may from time to time thereafter change
the public offering price and other selling terms.  To the extent, if at all,
that any Option Shares are purchased pursuant to Section 2 hereof, the
Underwriters will offer them to the public on the foregoing terms.

     It is further understood that you will act as the Representatives for the
Underwriters in the offering and sale of the Shares in accordance with a Master
Agreement Among Underwriters entered into by you and the several other
Underwriters.

     4.  Covenants of the Company.

     (a) The Company covenants and agrees with the several Underwriters that:

          (i) The Company will (i) prepare and timely file with the Commission
     under Rule 424(b) of the Rules and Regulations a Prospectus containing
     information previously omitted at the time of effectiveness of the
     Registration Statement in reliance on Rule 430A of the Rules and
     Regulations, (ii) not file any amendment to the Registration Statement or
     supplement to the Prospectus or documents incorporated by reference
     therein of which the Representatives shall not previously have been
     advised and furnished with a copy or to which the Representatives shall
     have reasonably objected in writing or which is not in compliance with the
     Rules and Regulations and (iii) file on a timely basis all reports and any
     definitive proxy or information statements required to be filed by the
     Company with the Commission subsequent to the date of the Prospectus and
     prior to the termination of the offering of the Shares by the
     Underwriters.

          (ii) The Company will advise the Representatives promptly of any
     request of the Commission for amendment of the Registration Statement or
     for supplement to the Prospectus or for any additional information, or of
     the issuance by the Commission of any stop order suspending the
     effectiveness of the Registration Statement or the use of the Prospectus
     or of the institution of any proceedings for that purpose, and the Company
     will use its best efforts to prevent the issuance of any such stop order
     preventing or suspending the use of the Prospectus and to obtain as soon
     as possible the lifting thereof, if issued.            

          (iii) The Company will deliver to, or upon the order of, the
     Representatives, from time to time, as many copies of any Preliminary
     Prospectus as the Representatives may reasonably request.  The Company
     will deliver to, or upon the order of, the Representatives during the
     period when delivery of a Prospectus is required under the Act, as many
     copies of the Prospectus in final form, or as thereafter amended or
     supplemented, as the Representatives may 

                                     - 11 -
<PAGE>   12

     reasonably request.  The Company will deliver to the Underwriters at or 
     before the Closing Date, four signed copies of the Registration Statement 
     and all amendments thereto including all exhibits filed therewith, and 
     will deliver to the Underwriters such number of copies of the Registration
     Statement, but without exhibits, and of all amendments thereto, as the 
     Representatives may reasonably request.

          (iv) If during the period in which a prospectus is required by law to
     be delivered by an Underwriter or dealer any event shall occur as a result
     of which, in the judgment of the Company or in the reasonable opinion of
     counsel for the Underwriters, it becomes necessary to amend or supplement
     the Prospectus in order to make the statements therein, in the light of
     the circumstances existing at the time the Prospectus is delivered to a
     purchaser, not misleading, or, if it is necessary at any time to amend or
     supplement the Prospectus to comply with any law, the Company promptly
     will either (i) prepare and file with the Commission an appropriate
     amendment to the Registration Statement or supplement to the Prospectus or
     (ii) prepare and file with the Commission an appropriate filing under the
     Securities Exchange Act of 1934 which shall be incorporated by reference
     in the Prospectus so that the Prospectus as so amended or supplemented
     will not, in the light of the circumstances when it is so delivered, be
     misleading, or so that the Prospectus will comply with law.

          (v) The Company will make generally available to its security
     holders, as soon as it is practicable to do so, but in any event not later
     than 15 months after the effective date of the Registration Statement, an
     earning statement (which need not be audited) in reasonable detail,
     covering a period of at least 12 consecutive months beginning after the
     effective date of the Registration Statement, which earning statement
     shall satisfy the requirements of Section 11(a) of the Act and Rule 158 of
     the Rules and Regulations and will advise you in writing when such
     statement has been so made available.

          (vi) The Company will, for a period of five years from the Closing
     Date, deliver to the Representatives copies of annual reports and copies
     of all other documents, reports and information furnished by the Company
     to its stockholders or filed with any securities exchange pursuant to the
     requirements of such exchange or with the Commission pursuant to the Act
     or the Securities Exchange Act of 1934, as amended.

          (vii) No offering, sale, short sale or other disposition of any
     Common Stock or other securities convertible into or exchangeable or
     exercisable for shares of Common Stock of the Company will be made for a
     period of 90 days after the date of this Agreement, directly or
     indirectly, by the Company otherwise than hereunder or with the prior
     written consent of the Representatives except that the Company may,
     without such consent, issue shares upon the exercise of options
     outstanding on the date of this Agreement issued pursuant to the Company's
     stock 

                                     - 12 -



<PAGE>   13



     option plans, issued as consideration for future acquisitions or issued 
     pursuant to the Company's dividend reinvestment plan.

          (ix) The Company will use its best efforts to list, subject to notice
     of issuance, the Shares on the Nasdaq National Market ("Nasdaq National
     Market").

     (b) The Selling Shareholders covenant and agree with the Underwriters and
the Company that:

           (i) No offering, sale or other disposition of any Common Stock of
      the Company held by such Selling Shareholder will be made for a period of
      90 days after the date of this Agreement otherwise than under this
      Agreement or with the prior written consent of the Representatives.

           (ii) In order to document the Underwriters' compliance with the
      reporting and withholding provisions of the Tax Equity and Fiscal
      Responsibility Act of 1982 and the Interest and Dividend Tax Compliance
      Act of 1983 with respect to the transactions herein contemplated, the
      Selling Shareholders agree to deliver to you prior to or at the Closing
      Date, a properly completed and executed United States Treasury Department
      Form W-9 (or other applicable form or statement specified by Treasury
      Department regulations in lieu thereof).

     5. Costs and Expenses.  The Company will pay all costs, expenses and fees
incident to the performance of the obligations of the Company under this
Agreement, including, without limiting the generality of the foregoing, the
following:  accounting fees of the Company; the fees and disbursements of
counsel for the Company; the cost of printing and delivering to, or as
requested by, the Underwriters copies of the Registration Statement,
Preliminary Prospectuses, the Prospectus, this Agreement, the Agreement Among
Underwriters, the Underwriters' Selling Memorandum, the Underwriters'
Questionnaire, the Invitation Letter, the Power of Attorney; the filing fees of
the Commission; and the filing fees and expenses incident to securing any
required review by the NASD of the terms of the sale of the Shares; the listing
on the Nasdaq National Market.  To the extent, if at all, that any of the other
Selling Shareholders engage special legal counsel to represent them in
connection with this offering, the fees and expenses of such counsel shall be
borne by such Selling Shareholder.  Any transfer taxes imposed on the sale of 
the Shares to the several Underwriters  will be paid by the Company and the 
Selling Shareholders pro rata.  The Selling Shareholders shall not, however, 
be required to pay for any of the Underwriters' expenses except that, if this 
Agreement shall not be consummated because the conditions in Section 7 hereof 
are not satisfied, or because this Agreement is terminated by the 
Representatives pursuant to Section 6 hereof, or by reason of any failure, 
refusal or inability on the part of any Seller to perform any undertaking or 
satisfy any condition of this Agreement or to comply with any of the terms 
hereof on its part to be performed, unless such failure to satisfy said 
condition or to comply with said terms be due to the default or omission of any 
Underwriter, then the 

                                     - 13 -


<PAGE>   14

Company shall reimburse the several Underwriters for reasonable out-of-pocket 
expenses, including fees and disbursements of counsel, reasonably incurred in 
connection with investigating, marketing and proposing to market the Shares or 
in contemplation of performing their obligations hereunder; but the Selling 
Shareholders shall not in any event be liable to any of the several
Underwriters for damages on account of loss of anticipated profits from the
sale by them of the Shares.

     6. Conditions of Obligations of the Underwriters.  The several obligations
of the Underwriters to purchase the Firm Shares on the Closing Date and the
Option Shares, if any, on the Option Closing Date are subject to the accuracy,
as of the Closing Date or the Option Closing Date, as the case may be, of the
representations and warranties of the Company contained herein, and to the
performance by the Company of its covenants and obligations hereunder and to
the following additional conditions:

     (a) The Registration Statement and all post-effective amendments thereto
shall have become effective and any and all filings required by Rule 424 and
Rule 430A of the Rules and Regulations shall have been made, and any request of
the commission for additional information (to be included in the Registration
Statement or otherwise) shall have been disclosed to the Underwriters and
complied with to their reasonable satisfaction. No stop order suspending the
effectiveness of the Registration Statement, as amended from time to time,
shall have been issued and no proceedings for that purpose shall have been
taken or, to the knowledge of the Company, shall be contemplated by the
Commission.

     (b) The Representatives shall have received on the Closing Date or the
Option Closing Date, as the case may be, the opinion of Morris, Manning &
Martin, counsel for the Company and the Selling Shareholders, dated the Closing
Date or the Option Closing Date, as the case may be, addressed to the
Underwriters to the effect that:

          (i) The Company has been duly organized and is validly existing as a
     corporation in good standing under the laws of the State of Georgia, with
     corporate power and authority to own its properties and conduct its
     business as described in the Prospectus; each of the Subsidiaries has been
     duly organized and is validly existing as a corporation (or, in the case
     of HNS, as a limited liability company) in good standing under the laws of
     the jurisdiction of its incorporation or organization, with corporate 
     power and authority to own its properties and conduct its business as 
     described in the Prospectus; the Company and each of the Subsidiaries are 
     duly qualified to transact business in all jurisdictions in which the 
     conduct of their business requires such qualification, or in which the 
     failure to qualify would have a materially adverse effect upon the 
     business of the Company or any of the Subsidiaries; and the outstanding 
     capital shares of each of the Subsidiaries have been validly issued, are 
     fully paid and non-assessable; and, to such counsel's knowledge, the 
     outstanding capital shares of each of the Subsidiaries owned by the 
     Company as described in the Registration Statement are owned free and 
     clear of all 

                                     - 14 -



<PAGE>   15

     liens, encumbrances and security interests, and no options, warrants or 
     other rights to purchase, such shares are outstanding.

          (ii) The Company has authorized and outstanding capital stock as set
     forth under the caption "Capitalization" in the Prospectus; the authorized
     shares of its Common Stock, have been duly authorized.

          (iii) The outstanding shares of the Company's Common Stock, including
     the Shares to be sold by the Selling Shareholders, have been duly
     authorized and validly issued and are fully paid and non-assessable; all
     of the Shares conform to the description thereof contained in the
     Prospectus; and the certificates for the Shares are in due and proper
     form.

          (iv) The shares of Common Stock to be sold by the Company pursuant to
     this Agreement have been duly authorized and will be validly issued, fully
     paid and non-assessable when issued and paid for as contemplated by this
     Agreement; and no preemptive rights of stockholders exist with respect to
     any of the Shares or the issue and sale thereof.

          (v) The Registration Statement has become effective under the Act
     and, to the best of the knowledge of such counsel, no stop order
     proceedings with respect thereto have been instituted or are pending or
     threatened under the Act.

          (vi) The Registration Statement, all Preliminary Prospectuses, the
     Prospectus and each amendment or supplement thereto and documents
     incorporated by reference therein (each as amended to date) comply as to
     form in all material respects with the requirements of the Act or the
     Exchange Act, as applicable, and the applicable rules and regulations
     thereunder (except that such counsel need express no opinion as to the
     financial statements, schedules and other financial information included
     or incorporated by reference therein).

          (vii) The statements under the caption "Description of Capital Stock"
     in the Prospectus, insofar as such statements constitute a summary of
     documents referred to therein or matters of law, are accurate summaries in
     all material respects and fairly present the information called for with 
     respect to such documents and matters.

          (viii) The statements under the caption "Business - Recent
     Developments" in the Prospectus, insofar as such statements constitute a
     summary of documents referred to therein, are accurate summaries in all
     material respects.

          (ix) Such counsel does not know of any contracts or documents 
     required to be filed as exhibits to the Registration Statement or 
     described in the Registration Statement or the Prospectus which are not so
     filed or described as required, and 

                                     - 15 -


<PAGE>   16

     such contracts and documents as are summarized in the Registration 
     Statement or the Prospectus are fairly summarized in all material respects.

          (x) Such counsel knows of no material legal proceedings or regulatory
     or other claims pending or threatened against the Company or any of the
     Subsidiaries except as set forth in the Prospectus.

          (xi) The execution and delivery of this Agreement and the
     consummation of the transactions herein contemplated do not and will not
     conflict with or result in a breach of any of the terms or provisions of,
     or constitute a default under, the Articles of Incorporation or Bylaws of
     the Company, or any agreement or instrument known to such counsel to which
     the Company is a party or by which the Company may be bound.

          (xii) This Agreement has been duly authorized, executed and delivered
     by the Company.

          (xiii) No approval, consent, order, authorization, designation,
     declaration or filing by or with any regulatory, administrative or other
     governmental body is necessary in connection with the execution and
     delivery of this Agreement and the consummation of the transactions herein
     contemplated (other than as may be required by the NASD or as required by
     State securities and Blue Sky laws as to which such counsel need express
     no opinion) except such as have been obtained or made, specifying the
     same.

          (xiv) To such counsel's knowledge, the Company is not, and will not
     become as a result of the consummation of the transactions contemplated by
     this Agreement, an "investment company" within the meaning of the
     Investment Company Act of 1940, as amended, and has not been an
     "investment company" at any time since 1988.

          (xv) This Agreement has been duly authorized, executed and delivered
     on behalf of the Selling Shareholders.

     In rendering such opinion, Morris, Manning & Martin may rely as to matters
governed by the laws of states other than Georgia or Federal laws on local
counsel in such jurisdictions and as to matters set forth in subparagraphs
(xiv), (xv) and (xvi) on an opinion of other counsel representing the Selling
Shareholders, provided that in each case Morris, Manning & Martin shall state
that they believe that they and the Underwriters are justified in relying on
such other counsel and such other counsel's opinion is also addressed to the
Underwriters.  In addition to the matters set forth above, such opinion shall
also include a statement to the effect that nothing has come to the attention
of such counsel which leads them to believe that the Registration Statement, as
of the time it 

                                     - 16 -
<PAGE>   17



became effective under the Act, the Prospectus or any amendment
or supplement thereto, on the date it was filed pursuant to Rule 424(b), as of
the date of effectiveness of the Registration Statement, as the case may be,
contain an untrue statement of a material fact or omit to state a material fact
required to be stated therein or necessary to make the statements therein not
misleading (except that such counsel need express no view as to financial
statements, schedules and other financial information included or incorporated
by reference therein).  With respect to such statement, Morris, Manning &
Martin may state that their belief is based upon the procedures set forth
therein, but is without independent check and verification.

     (c) The Representatives shall have received on the Closing Date or the
Option Closing Date, as the case may be, the opinion of _____________________,
counsel for the Selling Shareholders, dated the Closing Date or the Option
Closing Date, as the case may be, addressed to the Underwriters to the effect
that:

          (i) Each Selling Shareholder has been duly organized and is validly
     existing as a corporation in good standing under the laws of the
     jurisdiction of its incorporation with corporate power and authority to
     execute and deliver this Agreement.

          (ii) The execution and delivery of this Agreement and the Custodian
     Agreement executed by each Selling Shareholder and the consummation of the
     transactions contemplated herein and therein do not and will not conflict
     with or result in a breach of any of the terms or provisions of, or
     constitute a default under, the Articles of Incorporation or Bylaws of any
     Selling Shareholder, or any agreement or instrument known to such counsel
     to which the Selling Shareholder is a party or by which the Selling
     Shareholder may be bound.

          (iii) Each Selling Shareholder has full legal right, power and
     authority, and any approval required by law (other than as required by
     State securities and Blue Sky laws as to which such counsel need express
     no opinion), to sell assign, transfer and deliver the portion of the
     Shares to be sold by such Selling Shareholder.

          (iv) The Custodian Agreement and Power of Attorney executed and
     delivered by each Selling Shareholder are valid, irrevocable instruments
     legally sufficient for the respective purposes intended.

          (v) The Underwriters (assuming that they are bona fide purchasers
     within the meaning of the Uniform Commercial Code) will have acquired good
     and marketable title to the Shares being sold by each of the Selling
     Shareholders on the Closing Date or the Option Closing Date, as the case
     may be, free and clear of all claims, liens, encumbrances and security
     interests whatsoever.

                                     - 17 -
<PAGE>   18



     (d) The Representatives shall have received from Piper & Marbury L.L.P.,
counsel for the Representatives, an opinion dated the Closing Date or the
Option Closing Date, as the case may be, substantially to the effect specified
in subparagraphs (ii), (iv), (v) and (xii) of Paragraph (b) of this Section 6,
and that the Company is a validly organized and existing corporation under the
laws of the State of Georgia.  In rendering such opinion Piper & Marbury L.L.P.
may rely as to all matters governed other than by the laws of the State of
Maryland or Federal laws on the opinion of counsel referred to in paragraph (b)
of this Section 6.  In addition to the matters set forth above, such opinion
shall also include a statement to the effect that nothing has come to the
attention of such counsel which leads them to believe that the Registration
Statement, as of the time it became effective under the Act, and the Prospectus
or any amendment or supplement thereto, on the date it was filed pursuant to
Rule 424(b) and the Registration Statement and the Prospectus, or any amendment
or supplement thereto, as of the Closing Date or the Option Closing Date, as
the case may be, contain an untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary to make the
statements therein not misleading (except that such counsel need express no
view as to financial statements, schedules and other financial information
included or incorporated by reference therein).  With respect to such
statement, Piper & Marbury L.L.P. may state that their belief is based upon the
procedures set forth therein, but is without independent check and
verification.

     (e) The Representatives shall have received on the Closing Date or the
Option Closing Date, as the case may be, a signed letter from KPMG Peat Marwick
LLP and Ciulla, Smith & Dale, LLP, dated the Closing Date or the Option Closing
Date, as the case may be, which shall confirm, on the basis of a review in
accordance with the procedures set forth in the letter signed by such firm and
dated and delivered to the Representatives on the date hereof that nothing has
come to their attention during the period from the date five days prior to the
date hereof, to a date not more than five days prior to the Closing Date or the
Option Closing Date, as the case may be, which would require any change in
their letter dated the date hereof if it were required to be dated and
delivered on the Closing Date or the Option Closing Date, as the case may be.
All such letters shall be in form and substance reasonably satisfactory to the
Representatives.

     (f) The Representatives shall have received on the Closing Date or the
Option Closing Date, as the case may be, a certificate or certificates of the
Chief Executive Officer and the President and Chief Operating Officer of the
Company to the effect that, as of the Closing Date or the Option Closing Date,
as the case may be, each of them severally represents as follows:

         (i) The Registration Statement has become effective under the Act and
     no stop order suspending the effectiveness of the Registration Statement
     has been issued, and no proceedings for such purpose have been taken or
     are, to such officer's knowledge, contemplated by the Commission.

                                     - 18 -
<PAGE>   19

          (ii) Such officer does not know of any litigation instituted or
     threatened against the Company of a character required to be disclosed in
     the Registration Statement which is not so disclosed; such officer does
     not know of any material contract required to be filed as an exhibit to
     the Registration Statement which is not so filed; and the representations
     and warranties of the Company contained in Section 1 hereof are true and
     correct as of the Closing Date or the Option Closing Date, as the case may
     be.

          (iii) Such officer has carefully examined the Registration Statement
     and the Prospectus and, in such officer's opinion, as of the effective
     date of the Registration Statement, the statements contained in the
     Registration Statement were true and correct, and such Registration
     Statement and Prospectus did not omit to state a material fact required to
     be stated therein or necessary in order to make the statements therein not
     misleading and, in such officer's opinion, since the effective date of the
     Registration Statement, no event has occurred which should have been set
     forth in a supplement to or an amendment of the Prospectus which has not
     been so set forth in such supplement or amendment.

     (g) The Selling Shareholders shall have furnished to the Representatives
such further certificates and documents confirming the representations and
warranties contained herein and related matters as the Representatives may
reasonably have requested.

     (h) The Firm Shares, and Option Shares, if any, have been approved for
listing upon official notice of issuance on the Nasdaq National Market System.

     (i) The Representatives shall have received from each officer and director
of the Company and each Selling Shareholder, a letter or letters, in form and
substance satisfactory to the Underwriters, pursuant to which such person shall
agree not to offer, sell, sell short or otherwise dispose of any shares of
Common Stock of the Company or other capital stock of the Company, or any other
securities convertible, exchangeable or exercisable for Common Stock or
derivative of Common Stock owned by such person (or as to which such person has
the right to direct the disposition of) for a period of 90 days after the date 
of this Agreement, except with the prior written consent of the Underwriters.

     The opinions and certificates mentioned in this Agreement shall be deemed
to be in compliance with the provisions hereof only if they are in all material
respects satisfactory to the Representatives and to Piper & Marbury L.L.P.,
counsel for the Underwriters.

     If any of the conditions herein above provided for in this Section 6 shall
not have been fulfilled when and as required by this Agreement to be fulfilled,
the obligations of the Underwriters hereunder may be terminated by the
Representatives by notifying the Company of such termination in writing, by
facsimile, or by telegram at or prior to the 





                                     - 19 -
<PAGE>   20


Closing Date or the Option Closing Date, as the case may be.  In such event, 
the Company and the Selling Shareholders and the Underwriters shall not be
under any obligation to each other (except to the extent provided in Sections 5
and 8 hereof).

     7. Conditions of the Obligations of the Selling Shareholders.  The
obligations of the Selling Shareholders to sell and deliver the portion of the
Shares required to be delivered as and when specified in this Agreement are
subject to the conditions that at the Closing Date or the Option Closing Date,
as the case may be, no stop order suspending the effectiveness of the
Registration Statement shall have been issued and in effect or proceedings
therefor initiated or threatened.

     8. Indemnification

     (a) The Company and each Selling Shareholder agrees to indemnify and hold
harmless each Underwriter and each person, if any, who controls any Underwriter
within the meaning of the Act against any losses, claims, damages or
liabilities to which such Underwriter or such controlling person may become
subject under the Act or otherwise, insofar as such losses, claims, damages or
liabilities (or actions or proceedings in respect thereof) arise out of or are
based upon (i) any untrue statement or alleged untrue statement of any material
fact contained in the Registration Statement, any Preliminary Prospectus, the
Prospectus or any amendment or supplement thereto, or (ii) the omission or
alleged omission to state therein a material fact required to be stated therein
or necessary to make the statements therein not misleading, and will reimburse
each Underwriter and each such controlling person for any legal or other
expenses reasonably incurred by such Underwriter or such controlling person in
connection with investigating or defending any such loss, claim, damage,
liability, action or proceeding; provided, however, that the Company and the
Selling Shareholders will not be liable in any such case to the extent that (i)
any such loss, claim, damage or liability arises out of or is based upon an
untrue statement or alleged untrue statement, or omission or alleged omission
made in the Registration Statement, any Preliminary Prospectus, the Prospectus,
or such amendment or supplement, in reliance upon and in conformity with
written information furnished to the Company by or through the Representatives 
specifically for use in the preparation thereof or, (ii) such statement or 
omission was contained or made in any Preliminary Prospectus and corrected in 
the Prospectus and (a) any such loss, claim, damage or liability suffered or 
incurred by any Underwriter (or any person who controls any Underwriter) 
resulted from an action, claim or suit by any person who purchased Shares which
are the subject thereof from such Underwriter in the offering and (b) such 
Underwriter failed to deliver or provide a copy of the Prospectus to such 
person at or prior to the confirmation of the sale of such Shares in any case 
where such delivery is required by the Act.  In no event, however, shall the 
aggregate liability of any Selling Shareholder for indemnification under this 
Section 8(a) exceed the lesser of (i) that proportion of the total of such 
losses, claims, damages or liabilities indemnified against equal to the 
proportion of the total Shares sold hereunder which is being sold by such
Selling Shareholder, or (ii) the net proceeds after underwriters discounts and 
commissions 

                                     - 20 -
<PAGE>   21

received by such Selling Shareholder from the Underwriters in the offering.  
This indemnity agreement will be in addition to any liability which the Company
or the Selling Shareholders may otherwise have.

     (b) Each Underwriter will indemnify and hold harmless the Company, each of
its directors, each of its officers who have signed the Registration Statement,
each of the Selling Shareholders, and each person, if any, who controls the
Company within the meaning of the Act, against any losses, claims, damages or
liabilities to which the Company or any such director, officer, Selling
Shareholder or controlling person may become subject under the Act or
otherwise, insofar as such losses, claims, damages or liabilities (or actions
or proceedings in respect thereof) arise out of or are based upon any untrue
statement or alleged untrue statement of any material fact contained in the
Registration Statement, any Preliminary Prospectus, the Prospectus or any
amendment or supplement thereto, or arise out of or are based upon the omission
or the alleged omission to state therein a material fact required to be stated
therein or necessary to make the statements therein not misleading in the light
of the circumstances under which they were made; and will reimburse any legal
or other expenses reasonably incurred by the Company or any such director,
officer, Selling Shareholder or controlling person in connection with
investigating or defending any such loss, claim, damage, liability, action or
proceeding; provided, however, that each Underwriter will be liable in each
case to the extent, but only to the extent, that such untrue statement or
alleged untrue statement or omission or alleged omission has been made in the
Registration Statement, any Preliminary Prospectus, the Prospectus or such
amendment or supplement, in reliance upon and in conformity with written
information furnished to the Company by or through the Representatives
specifically for use in the preparation thereof.  This indemnity agreement will
be in addition to any liability which such Underwriter may otherwise have.

     (c) In case any proceeding (including any governmental investigation)
shall be instituted involving any person in respect of which indemnity may be
sought pursuant to this Section 8, such person (the "indemnified party") shall
promptly notify the person against whom such indemnity may be sought (the 
"indemnifying party") in writing.  No indemnification provided for in Section 
8(a) or (b) shall be available to any party who shall fail to give notice as 
provided in this Section 8(c) if the party to whom notice was not given was
unaware of the proceeding to which such notice would have related and was 
prejudiced by the failure to give such notice, but the failure to give such 
notice shall not relieve the indemnifying party or parties from any liability 
which it or they may have to the indemnified party for contribution or 
otherwise than on account of the provisions of Section 8(a) or (b).  In case 
any such proceeding shall be brought against any indemnified party and it shall
notify the indemnifying party of the commencement thereof, the indemnifying
party shall be entitled to participate therein and, to the extent that it shall
wish, jointly with any other indemnifying party similarly notified, to assume 
the defense thereof, with counsel satisfactory to such indemnified party and 
shall pay as incurred the fees and disbursements of such counsel related to 
such proceeding.  In any

                                     - 21 -
<PAGE>   22

such proceeding, any indemnified party shall have the right to retain its own
counsel at its own expense.  Notwithstanding the foregoing, the indemnifying
party shall pay as incurred the fees and expenses of the counsel retained by
the indemnified party in the event (i) the indemnifying party and the
indemnified party shall have mutually agreed to the retention of such counsel
or (ii) the named parties to any such proceeding (including any impleaded
parties) include both the indemnifying party and the indemnified party and
representation of both parties by the same counsel would be inappropriate due
to actual or potential differing interests between them.  It is understood that
the indemnifying party shall not, in connection with any proceeding or related
proceedings in the same jurisdiction, be liable for the reasonable fees and
expenses of more than one separate firm for all such indemnified parties.  Such
firm shall be designated in writing by you in the case of parties indemnified
pursuant to Section 8(a) and by the Company in the case of parties indemnified
pursuant to Section 8(b).  The indemnifying party shall not be liable for any
settlement of any proceeding effected without its written consent but if
settled with such consent or if there be a final judgment for the plaintiff,
the indemnifying party agrees to indemnify the indemnified party from and
against any loss or liability by reason of such settlement or judgment.

     (d) If the indemnification provided for in this Section 8 is unavailable
to or insufficient to hold harmless an indemnified party under Section 8(a) or
(b) above in respect of any losses, claims, damages or liabilities (or actions
or proceedings in respect thereof) referred to therein, then each indemnifying
party shall contribute to the amount paid or payable by such indemnified party
as a result of such losses, claims, damages or liabilities (or actions or
proceedings in respect thereof) in such proportion as is appropriate to reflect
the relative benefits received by the Company and the Selling Shareholders on
the one hand and the Underwriters on the other from the offering of the Shares.
If, however, the allocation provided by the immediately preceding sentence is
not permitted by applicable law or if the indemnified party failed to give the
notice required under Section 8(c) above, then each indemnifying party shall
contribute to such amount paid or payable by such indemnified party in such
proportion as is appropriate to reflect not only such relative benefits but 
also the relative fault of the Company and the Selling Shareholders on the one 
hand and the Underwriters on the other in connection with the statements or 
omissions which resulted in such losses, claims, damages or liabilities (or 
actions or proceedings in respect thereof), as well as any other relevant
equitable considerations.  The relative benefits received by the Company and 
the Selling Shareholders on the one hand and the Underwriters on the other 
shall be deemed to be in the same proportion as the total net proceeds from the
offering (before deducting expenses) received by the Company and the Selling
Shareholders bear to the total underwriting discounts and commissions received
by the Underwriters, in each case as set forth in the table on the cover page
of the Prospectus.  The relative fault shall be determined by reference to,
among other things, whether the untrue or alleged untrue statement of a
material fact or the omission or alleged omission to state a material fact
relates to information supplied by the Company and the Selling Shareholders on
the one 

                                     - 22 -
<PAGE>   23

hand or the Underwriters on the other and the parties' relative intent,
knowledge, access to information and opportunity to correct or prevent such
statement or omission.

     The Company, the Selling Shareholders and the Underwriters agree that it
would not be just and equitable if contributions pursuant to this Section 8(d)
were determined by pro rata allocation (even if the Underwriters were treated
as one entity for such purpose) or by any other method of allocation which does
not take account of the equitable considerations referred to above in this
Section 8(d).  The amount paid or payable by an indemnified party as a result
of the losses, claims, damages or liabilities (or actions or proceedings in
respect thereof) referred to above in this Section 8(d) shall be deemed to
include any legal or other expenses reasonably incurred by such indemnified
party in connection with investigating or defending any such action or claim.
Notwithstanding the provisions of this subsection (d), (i) no Underwriter shall
be required to contribute any amount in excess of the underwriting discounts
and commissions applicable to the Shares purchased by such Underwriter, (ii) no
person guilty of fraudulent misrepresentation (within the meaning of Section
11(f) of the Act) shall be entitled to contribution from any person who was not
guilty of such fraudulent misrepresentation, and (iii) no Selling Shareholder
shall be required to contribute any amount in excess of the lesser of (A) that
proportion of the total of such losses, claims, damages or liabilities
indemnified or contributed against equal to the proportion of the total Shares
sold hereunder which is being sold by such Selling Shareholder, or (B) the net
proceeds after underwriting discounts and commissions received by such Selling
Shareholder from the Underwriters in the offering.  The Underwriters'
obligations in this Section 8(d) to contribute are several in proportion to
their respective underwriting obligations and not joint.

     (e) In any proceeding relating to the Registration Statement, any
Preliminary Prospectus, the Prospectus or any supplement or amendment thereto,
each party against whom contribution may be sought under this Section 8 hereby
consents to the jurisdiction of any court having jurisdiction over any other
contributing party, agrees that process issuing from such court may be served 
upon him or it by any other contributing party and consents to the service of 
such process and agrees that any other contributing party may join him or it as
an additional defendant in any such proceeding in which such other contributing
party is a party.

     9. Default by Underwriters.  If on the Closing Date or the Option Closing
Date, as the case may be, any Underwriter shall fail to purchase and pay for
the portion of the Shares which such Underwriter has agreed to purchase and pay
for on such date (otherwise than by reason of any default on the part of the
Company or the Selling Shareholders), you, as the Representatives of the
Underwriters, shall use your best efforts to procure within 24 hours thereafter
one or more other Underwriters, or any others, to purchase from the Company and
the Selling Shareholders such amounts as may be agreed upon and upon the terms
set forth herein, the Firm Shares or Option Shares, as the case may be, which
the defaulting Underwriter or Underwriters failed to purchase.  If during 

                                     - 23 -
<PAGE>   24

such 24 hours you as such Representatives, shall not have procured such other
Underwriters, or any others, to purchase the Firm Shares or Option Shares, as
the case may be, agreed to be purchased by the defaulting Underwriter or
Underwriters, then (a) if the aggregate number of shares with respect to which
such default shall occur does not exceed 10% of the Firm Shares or Option
Shares, as the case may be, covered hereby, the other Underwriters shall be
obligated, severally, in proportion to the respective numbers of Firm Shares or
Option Shares, as the case may be, which they are obligated to purchase
hereunder, to purchase the Firm Shares or Option Shares, as the case may be,
which such defaulting Underwriter or Underwriters failed to purchase, or (b) if
the aggregate number of shares of Firm Shares or Option Shares, as the case may
be, with respect to which such default shall occur exceeds 10% of the Firm
Shares or Option Shares, as the case may be, covered hereby, the Company or you
as the Representatives of the Underwriters will have the right, by written
notice given within the next 24-hour period to the parties to this Agreement,
to terminate this Agreement without liability on the part of the non-defaulting
Underwriters or of the Company and the Selling Shareholders except to the
extent provided in Section 8 hereof.  In the event of a default by any
Underwriter or Underwriters, as set forth in this Section 9, the Closing Date
or Option Closing Date, as the case may be, may be postponed for such period,
not exceeding seven days, as you, as Representatives, may determine in order
that the required changes in the Registration Statement or in the Prospectus or
in any other documents or arrangements may be effected.  The term "Underwriter"
includes any person substituted for a defaulting Underwriter.  Any action taken
under this Section 9 shall not relieve any defaulting Underwriter from
liability in respect of any default of such Underwriter under this Agreement.

     10. Notices.  All communications hereunder shall be in writing and, except
as otherwise provided herein, will be mailed, delivered or telegraphed and
confirmed as follows:  if to the Underwriters, to Alex. Brown & Sons
Incorporated, 1 South Street, Baltimore, Maryland 21202, Attention:  David
Weaver, Principal; if to the Company or the Selling Shareholders, to Harbinger
Corporation, 1055 Lenox Park Boulevard, Atlanta, Georgia  30319, Attention: C. 
Tycho Howle, Chairman of the Board.

     11. Termination.  This Agreement may be terminated by you by notice to the
Company as follows:

     (a) at any time prior to the earlier of (i) the time the Shares are
released by you for sale by notice to the Underwriters, or (ii) 11:30 A.M. on
the first business day following the date of this Agreement;

     (b) at any time prior to the Closing Date if any of the following has
occurred:  (i) since the respective dates as of which information is given in
the Registration Statement and the Prospectus, any material adverse change or
any development involving a prospective material adverse change in or affecting
the condition, financial or otherwise, of the Company or the earnings, business
affairs, management or business 

                                     - 24 -
<PAGE>   25

prospects of the Company, whether or not arising in the ordinary course of 
business, (ii) any outbreak or escalation of hostilities or declaration of war 
or national emergency after the date hereof or other national or international 
calamity or crisis or change in economic or political conditions if the effect 
of such outbreak, escalation, declaration, emergency, calamity, crisis or 
change on the financial markets of the United States would, in your reasonable 
judgment, make the offering or delivery of the Shares impracticable, (iii) 
trading in securities on the New York Stock Exchange or the American Stock 
Exchange shall have been suspended or materially limited (other than 
limitations on hours or numbers of days of trading) or minimum prices shall 
have been established  for securities on either such Exchange, (iv) the 
enactment, publication, decree or other promulgation of any federal or state 
statute, regulation, rule or order of any court or other governmental authority
which in your reasonable opinion materially and adversely affects or will 
materially or adversely affect the business or operations of the Company, (v) 
declaration of a banking moratorium by either federal or New York State 
authorities, (vi) the taking of any action by any governmental body or agency 
in respect of its monetary or fiscal affairs which in your reasonable opinion 
has a material adverse effect on the securities markets in the United States or
elsewhere, or (vii) any litigation or proceeding is pending or threatened 
against the Underwriters which seeks to enjoin or otherwise restrain, or seeks 
damages in connection with, or questions the legality or validity of this 
Agreement or the transactions contemplated hereby; or

     (c) as provided in Sections 6 and 9 of this Agreement.

     This Agreement also may be terminated by you, by notice to the Company and
the Selling Shareholders, as to any obligation of the Underwriters to purchase
the Option Shares, upon the occurrence at any time prior to the Option Closing
Date of any of the events described in subparagraph (b) above or as provided in
Sections 6 and 9 of this Agreement.

     12. Successors.  This Agreement has been and is made solely for the
benefit of the Underwriters, the Company and the Selling Shareholders and their
respective successors, executors, administrators, heirs and assigns, and the
officers, directors and controlling persons referred to herein, and no other
person will have any right or obligation hereunder. The term "successors" shall
not include any purchaser of the Shares merely because of such purchase.

     13. Miscellaneous.  The reimbursement, indemnification and contribution
agreements contained in this Agreement and the representations, warranties and
covenants in this Agreement shall remain in full force and effect regardless of
(a) any termination of this Agreement, (b) any investigation made by or on
behalf of any Underwriter or controlling person thereof, or by or on behalf of
the Company or its directors or officers and (c) delivery of and payment for
the Shares under this Agreement.


                                     - 25 -


<PAGE>   26


     This Agreement may be executed in two or more counterparts, each of which
shall be deemed an original, but all of which together shall constitute one and
the same instrument.

     This Agreement shall be governed by, and construed in accordance with, the
laws of the State of Maryland.

     If the foregoing letter is in accordance with your understanding of our
agreement, please sign and return to us the enclosed duplicates hereof,
whereupon it will become a binding agreement among the Company, the Selling
Shareholders and the several Underwriters in accordance with its terms.


                                Very truly yours,                               
                                                                                
                                HARBINGER CORPORATION                           
                                                                                
                                                                                
                                By 
                                   ---------------------------------          
                                   C. Tycho Howle                   
                                   Chairman                         
                                                                                
                                Selling Shareholders listed on Schedule II      
                                                                                
                                                                                
                                By  
                                  -----------------------------------
                                  [Joel G. Katz, Attorney-in-Fact]            

The foregoing Underwriting Agreement
is hereby confirmed and accepted as
of the date first above written.

ALEX. BROWN & SONS INCORPORATED
ROBERTSON, STEPHENS & COMPANY LLC
THE ROBINSON-HUMPHREY COMPANY, INC.
INTERSTATE JOHNSON LANE CORPORATION
As Representatives of the Several Underwriters listed
on Schedule I

By ALEX. BROWN & SONS INCORPORATED


By
  ---------------------------------
    Authorized Officer


                                     - 26 -
<PAGE>   27

                                   SCHEDULE I

                            SCHEDULE OF UNDERWRITERS

<TABLE>
<CAPTION>
                                     Number of Firm Shares
       Underwriter                      to be Purchased
       -----------                   ---------------------
<S>                                       <C>           
Alex. Brown & Sons Incorporated
The Robinson-Humphrey Company, Inc.
Robertson, Stephens & Company, L.P.
Interstate/Johnson Lane Corporation                 
                                          --------- 
                 Total                    2,900,000 
</TABLE>                                  ========= 


                                     - 27 -
<PAGE>   28


                                  SCHEDULE II

                        SCHEDULE OF SELLING SHAREHOLDERS



<TABLE>
<CAPTION>
                                        Number of      Maximum Number 
                                                      of Option Shares 
            Name of Seller               Shares          to be Sold
            --------------               ------       ----------------
<S>                                     <C>                 <C>
Harbinger Corporation                   1,800,000           270,000            

Vulcan Ventures, Inc.                     500,000            75,000            

AXA Equity & Law Assurance 
Society Plc                               300,000            45,000            

Orbis Pension Trustees Limited            300,000            45,000            

                                 Total  2,900,000           435,000            
</TABLE>


                                     - 28 -

<PAGE>   1



                                                                EXHIBIT 23.1




                          INDEPENDENT AUDITORS' CONSENT

The Board of Directors
Harbinger Corporation

   
We consent to the use of our reports dated May 13, 1997, relating to the
consolidated balance sheets of Harbinger Corporation as of December 31, 1996 and
1995, and the related consolidated statements of operations, shareholders'
equity, and cash flows for each of the years in the two-year period ended
December 31, 1996, and the related financial statement schedule, which reports
appear in Harbinger Corporation's Current Report on Form 8-K filed on July 1,
1997 and are incorporated by reference in Amendment No.2 to the Form S-3
registration statement of Harbinger Corporation and to the reference to our
firm under the heading "Experts" in the Prospectus.
    

Our reports dated May 13, 1997, included a reference to other auditors with
respect to 1995, as those reports, as they relate to the 1995 combined financial
statements for Supply Tech, Inc. and Supply Tech International, LLC which are
included in the consolidated financial statements of Harbinger Corporation, are
based solely on the report of the other auditors as it relates to the amounts
included for Supply Tech, Inc. and Supply Tech International, LLC. Our reports
dated May 13, 1997 also indicated that the financial statements of Harbinger
Corporation and Supply Tech, Inc. and Supply Tech International, LLC for 1994
were audited by other auditors, although the reports also indicated that we
audited the combination of the accompanying financial statements and financial
statement schedule for 1994.


                                                   KPMG Peat Marwick LLP
   
Atlanta, Georgia
July 25, 1997
    



<PAGE>   2


                                                                   EXHIBIT 23.1






                          INDEPENDENT AUDITORS' CONSENT



The Board of Directors
Harbinger Corporation:

   
We consent to the use of our report dated February 19, 1997 relating to the
combined balance sheet of Supply Tech, Inc. and Supply Tech International, LLC
as of December 31, 1996 and the related combined statements of operations,
shareholders' equity (deficit), and cash flows for the year then ended included
in Harbinger Corporation's Current Report on Form 8-K/A Amendment No. 1 filed on
March 18, 1997 and incorporated by reference in Amendment No.2 to the Form S-3
registration statement of Harbinger Corporation and to the reference to our
firm under the heading "Experts" in the Prospectus.
    

                                                       KPMG Peat Marwick LLP




   
Atlanta, Georgia
July 25, 1997
    

<PAGE>   3


                                                                  EXHIBIT 23.1





                          INDEPENDENT AUDITORS' CONSENT

The Board of Directors
Harbinger Corporation:

   
We consent to the use of our report dated February 7, 1997 relating to the
balance sheets of Harbinger Net Services, LLC as of December 31, 1996 and 1995,
and the related statements of operations, shareholders' equity, and cash flows
for the periods ended December 31, 1996 and 1995 included in Harbinger
Corporation's Current Report on Form 8-K/A Amendment No. 1 filed on March 14,
1997 and incorporated by reference in Amendment No. 2 to the Form S-3 
registration statement of Harbinger Corporation and to the reference to our 
firm under the heading "Experts" in the Prospectus.
    

                                                KPMG Peat Marwick LLP
   
Atlanta, Georgia
July 25, 1997
    




<PAGE>   1

                                                                    EXHIBIT 23.2







                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS


   
As independent public accountants, we hereby consent to the incorporation by
reference in Amendment No. 2 to this Form S-3 Registration Statement of our 
report dated March 14, 1995 included in Harbinger Corporation's Current Report 
on Form 8-K filed on July 1, 1997 and to all references to our firm included 
in Amendment No.2 to this registration statement.
    

                               Arthur Andersen LLP



   
Atlanta, Georgia
July 25, 1997
    

<PAGE>   1


                                                                   EXHIBIT 23.3






                          INDEPENDENT AUDITORS' CONSENT



The Board of Directors
Harbinger Corporation:

   
We consent to the use of our report dated February 19, 1997 relating to the
combined balance sheet of Supply Tech, Inc. and Supply Tech International, LLC
as of December 31, 1995 and the related combined statements of operations,
shareholders' equity (deficit), and cash flows for each of the years in the
two-year period ended December 31, 1995 included in Harbinger Corporation's
Current Report on Form 8-K/A Amendment No. 1 filed on March 18, 1997 and
Harbinger Corporation's Current Report on Form 8-K filed on July 1, 1997 and
incorporated by reference in Amendment No. 2 to the Form S-3 registration
statement of Harbinger Corporation.
    


                            Ciulla, Smith & Dale, LLP





   
Southfield, Michigan
July 25, 1997
    



<PAGE>   1


                                                                   EXHIBIT 23.4







                          INDEPENDENT AUDITORS' CONSENT



The Board of Directors
Harbinger Corporation:

   
We consent to the use of our report dated June 14, 1996 relating to the
consolidated balance sheets of NTEX Holding B.V. as of December 31, 1995, and
the related consolidated statements of operations, shareholders' equity, and
cash flows for the year then ended included in Harbinger Corporation's Current
Report on Form 8-K/A Amendment No. 1 filed on June 17, 1996 and incorporated by
reference in Amendment No. 2 to the Form S-3 registration statement of Harbinger
Corporation.
    


                         Moret Ernst & Young Accountants





   
The Hague
July 25, 1997
    



<PAGE>   1


                                                                   EXHIBIT 23.5






                          INDEPENDENT AUDITORS' CONSENT



The Board of Directors
Harbinger Corporation:

   
We consent to the use of our report dated June 11, 1996 relating to the balance
sheet of INOVIS GmbH & Co. computergestuzte Informationssysteme as of December
31, 1995 and the related statements of operations and accumulated deficit,
partners' equity, and cash flows for the year then ended included in Harbinger
Corporation's Form 8-K/A Amendment No. 1 filed on July 1, 1996 and incorporated
by reference in Amendment No. 2 to  the Form S-3 registration statement of 
Harbinger Corporation and to the reference to our firm under the heading 
"Experts" in the Prospectus.
    


                                    KPMG Deutsche Treuhand-Gesellschaft AG 



   
Germany
July 25, 1997
    



<PAGE>   1


                                                                   EXHIBIT 23.6







                          INDEPENDENT AUDITORS' CONSENT



The Board of Directors
Harbinger Corporation:

   
We consent to the use of our report dated June 5, 1996 relating to the
consolidated balance sheets of Harbinger N.V. and subsidiaries as of December
31, 1995, 1994 and 1993 and the related consolidated statements of operations,
shareholders' equity, and cash flows for the two years ended December 31, 1995
and 1994 and the one month ended December 31, 1993 included in Harbinger
Corporation's Current Report on Form 8-K/A Amendment No. 1 filed on July 2, 1996
and incorporated by reference in Amendment No. 2 to the Form S-3 registration 
statement of Harbinger Corporation and to the reference to our firm under the 
heading "Experts" in the Prospectus.
    


                                                KPMG Accountants N.V.





   
The Hague
July 25, 1997
    



<PAGE>   1


                                                                   EXHIBIT 23.7






                         CONSENT OF INDEPENDENT AUDITORS



   
We consent to the reference to our firm under the caption "Experts" in the
registration statement (Amendment No. 2 to Form S-3) and related Prospectus of
Harbinger Corporation for the registration of up to 3,335,000 shares of its
common stock and to the incorporation therein of our report dated April 28,
1995, with respect to the statement of operations of EDI (formerly a business
of Texas Instruments, Incorporated) for the year ended December 31, 1994
included in Harbinger Corporation's registration statement (Form S-1, No.
33-93804) filed with the Securities and Exchange Commission.
    


                                            Ernst & Young LLP





   
Atlanta, Georgia
July 28, 1997
    



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