CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
We consent to the incorporation by reference
in the Registration Statements on Form S-8 (File No.
333-80177, 333-82249, 333-51878, 333-76272, 333-87618, 333-102434, 333-104169, 333-109895,
333-112022, 333-116187, 333-122054, 333-124092 and 333-146195) of F5 Networks, Inc., of our report
dated August 6, 2007, with respect to the consolidated financial statements of Acopia Networks,
Inc. and Subsidiaries, included in the Current Report on Form 8-K/A of F5 Networks, Inc. dated
September 12, 2007.
Boston, Massachusetts
November 16, 2007