EXHIBIT 5.1
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PIPER
MARBURY
RUDNICK
& WOLFE LLP
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Suite 610, Commerce Executive Park III
1850 Centennial Park Drive
Reston, Virginia 20191-1517
www.piperrudnick.com
PHONE (703) 391-7100
FAX (703) 390-5299
May 30, 2000
Visual Networks, Inc.
2092 Gaither Road
Rockville, Maryland 20850
Ladies and Gentlemen:
We have acted as counsel to Visual Networks, Inc., a Delaware
Corporation (the "Company"), in connection with the preparation and filing with
the Securities and Exchange Commission of Post-Effective Amendment No. 1 on Form
S-8 to the registration statement on Form S-4 (the "Post-Effective Amendment")
registering 673,338 shares of Visual Networks, Inc. common stock, par value
$0.01 per share, issuable pursuant to the exercise of options granted under the
Avesta Technologies, Inc. 1996 Stock Plan, as amended and assumed by Visual
Networks, Inc. (the "Plan Shares").
We have examined copies of the Company's Amended and Restated
Certificate of Incorporation, Amended and Restated By-Laws, the Avesta
Technologies, Inc. 1996 Stock Plan, as amended and assumed by Visual Networks,
Inc. (the "Plan"), the Company's Registration Statement on Form S-4 filed on
April 4, 2000 (File No. 333-33946), as amended, the Agreement and Plan of Merger
by and among Visual Networks, Inc., Visual Acquisitions Three, Inc., and Avesta
Technologies, Inc., dated as of February 7, 2000, all resolutions adopted by the
Company's Board of Directors relating to the above and other records and
documents that we have deemed necessary for the purpose of this opinion. We have
also examined such other documents, papers, statutes and authorities as we have
deemed necessary to form a basis for this opinion. In our examination, we have
assumed the genuineness of all signatures and the conformity to original
documents of all copies submitted to us. As to various questions of fact
material to this opinion, we have relied on statements and certificates of
officers and representatives of the Company and others.
Based upon the foregoing, we are of the opinion that Plan Shares
issuable under the Plan have been duly authorized and will be (when issued, sold
and delivered as authorized) validly issued, fully paid and non-assessable.
The opinions set forth herein are limited to matters governed by the
laws of the State of Delaware and the Federal Laws of the United States of
America, and we express no opinion as to any other laws.
We hereby consent to the filing of this opinion as Exhibit 5.1 to the
Post-Effective Amendment.
Very truly yours,
/s/ Piper Marbury Rudnick & Wolfe LLP
