EXHIBIT 5.1
                                                                     -----------



                               February 4, 1997



International Network Services
1213 Innsbruck Drive
Sunnyvale, California 94089

     Re:  REGISTRATION STATEMENT ON FORM S-8

Ladies and Gentlemen:

     We have examined the Registration Statement on Form S-8 to be filed by you
with the Securities and Exchange Commission on or about February 4, 1997 (the
"Registration Statement"), in connection with the registration under the
Securities Act of 1933, as amended, of an aggregate of 9,948,835 shares of
Common Stock, no par value (the "Shares"), reserved for issuance pursuant to the
1996 Employee Stock Purchase Plan, the 1996 Stock Plan and the 1992 Flexible
Incentive Stock Plan (together, the "Plans"). As your legal counsel, we
have examined the proceedings taken and are familiar with the proceedings
proposed to be taken by you in connection with the sale and issuance of the
Shares under the Plans.

     It is our opinion that the Shares will be, when issued and sold in the
manner referred to in the Plans, 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 and any subsequent amendment thereto.

                              Very truly yours,
 
 
                              WILSON SONSINI GOODRICH & ROSATI
                              Professional Corporation

                              /s/ Wilson Sonsini Goodrich & Rosati