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EXHIBIT 5.1
[LETTERHEAD OF WILSON SONSINI GOODRICH & ROSATI]
August 31, 2000
CoSine Communications, Inc.
3200 Bridge Parkway
Redwood City, CA 94065
RE: REGISTRATION STATEMENT ON FORM S-1
Ladies and Gentlemen:
We have examined the Registration Statement on Form S-1 filed by you with
the Securities and Exchange Commission on April 28, 2000 (as such has been and
may be further amended or supplemented, the "Registration Statement") in
connection with the registration under the Securities Act of 1933, as amended
(the "Act"), of up to 11,500,000 shares of your Common Stock (the "Shares").
The Shares, which include up to 1,500,000 shares of Common Stock issuable
pursuant to an over-allotment option granted to the underwriters (the
"Underwriters"), are to be sold to the Underwriters for resale to the public as
described in the Registration Statement. As your counsel in connection with
this transaction, we have examined the proceedings proposed to be taken by you
in connection with the issuance and sale of the Shares.
Based on the foregoing, it is our opinion that, the Shares, when issued and
sold in the manner described in the Registration Statement, will be legally and
validly issued, fully paid and nonassessable.
We consent to the use of this opinion as an exhibit to the Registration
Statement, and further consent to the use of our name wherever appearing in the
Registration Statement, including the prospectus (the "Prospectus") constituting
a part thereof, which has been approved by us, as such may be further amended or
supplemented, or incorporated by reference in any registration statement filed
pursuant to Rule 462(b) of the Act that incorporates the Prospectus by
reference.
Sincerely,
WILSON SONSINI GOODRICH & ROSATI
Professional Corporation
/s/ WILSON SONSINI GOODRICH & ROSATI, P.C.
