EXHIBIT 99.1



                            CERTIFICATION PURSUANT TO
                             18 U.S.C. SECTION 1350,
                             AS ADOPTED PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

                    CERTIFICATION OF CHIEF EXECUTIVE OFFICER

               I, Daniel J. Warmenhoven, Chief Executive Officer of Network
Appliance, Inc. (the "Company"), pursuant to 18 U.S.C. Section 1350, as created
by Section 906 of the Sarbanes-Oxley Act of 2002, hereby certify to my knowledge
that:

              (i) the Quarterly Report on Form 10-Q of the Company for the
      quarterly period ended July 26, 2002 (the "Report") fully complies with
      the requirements of Section 13(a) or Section 15(d), as applicable, of the
      Securities Exchange Act of 1934, as amended; and

              (ii) the information contained in the Report fairly presents, in
      all material respects, the financial condition and results of operations
      of the Company.

Dated: August 29, 2002                  /s/  Daniel J. Warmenhoven
                                        ----------------------------------------
                                        Daniel J. Warmenhoven
                                        Chief Executive Officer

 CERTIFICATION OF SENIOR VICE PRESIDENT OF FINANCE AND CHIEF FINANCIAL OFFICER

               I, Steven J. Gomo, Senior Vice President of Finance and Chief
Financial Officer of Network Appliance, Inc. (the "Company"), pursuant to 18
U.S.C. Section 1350, as created by Section 906 of the Sarbanes-Oxley Act of
2002, hereby certify to my knowledge that:

              (i) the Quarterly Report on Form 10-Q of the Company for the
      quarterly period ended July 26, 2002 (the "Report") fully complies with
      the requirements of Section 13(a) or Section 15(d), as applicable, of the
      Securities Exchange Act of 1934, as amended; and

              (ii) the information contained in the Report fairly presents, in
      all material respects, the financial condition and results of operations
      of the Company.


Dated: August 29, 2002                  /s/  Steven J. Gomo
                                        ----------------------------------------
                                        Steven J. Gomo
                                        Senior Vice President of Finance and
                                        Chief Financial Officer