FOR IMMEDIATE RELEASE

CONTACTS:   Alane Moran                 Holly Hagerman
            F5 Networks, Inc.           Connect Public Relations
            206/272-6850                801/373-7888
            a.moran@f5.com              hollyh@connectpr.com

                F5 NETWORKS ACQUIRES LEADING WEB SECURITY COMPANY

                      F5 EXECUTES ON ITS PROMISE OF DELIVERING ENTERPRISE
       APPLICATION SECURITY THROUGH ACQUISITION OF MAGNIFIRE WEBSYSTEMS;
  TRAFFICSHIELD(TM) WEB FIREWALL IS AN ESSENTIAL COMPONENT TO PROTECT AGAINST
                           APPLICATION LEVEL ATTACKS

SEATTLE, JUNE 1, 2004 -- F5 Networks, Inc. (NASDAQ: FFIV), the leading provider
of Application Traffic Management products, today announced that it has acquired
MagniFire WebSystems, Inc. MagniFire is a technology leader in the web
application firewall market and is recognized as a visionary in Gartner's latest
Magic Quadrant for Enterprise Firewalls, 2H03. The $29 million cash transaction
for 100% of the equity of MagniFire was signed and closed on May 31, 2004.

      With this move, F5 is executing on its promise to protect enterprises from
malicious application level attacks. Unlike other security products, MagniFire's
TrafficShield(TM) security appliance protects against attacks that can
circumvent current network perimeter defenses. It combines robust
application-layer filtering with best-in-class network and encryption technology
for a complete Web security solution that effectively protects against
"zero-day" web infrastructure attacks, which are the most costly to businesses.
In addition, the TrafficShield product is the only solution that truly supports
dynamically changing content, which addresses one of the toughest challenges for
web application protection in most corporate applications. By employing
optimized real-time software for analysis of traffic at near wire speed, the
TrafficShield product is the fastest application protection system available and
ensures no impact on the user experience.

      "As part of our product requirements planning for F5's Application
Security Gateway, we solicited input from over 150 enterprises worldwide," said
John McAdam, President and CEO of F5 Networks. "These customers have been asking
us to apply our expertise in Application Traffic Management toward application
security and they helped define the criteria for a best-of-

breed solution. The acquisition of MagniFire gives us immediate access to
superior products and technology and TrafficShield's underlying design fits
perfectly into F5's overall architecture and product roadmap."

      The MagniFire acquisition is complementary to F5's successful acquisition
of uRoam and its FirePass SSL VPN product for secure remote access, last July.
The TrafficShield and FirePass product's web application security capabilities
enforce granular web application security policies, creating a complete and
reliable solution to protect organizations against any web application (Layer 7)
vulnerabilities. As the FirePass product secures user-to-application access, the
TrafficShield product ensures that only valid traffic reaches the application.

      MagniFire's TrafficShield technology implements a positive security model
that integrates readily with F5's Application Traffic Management architecture.
Unlike network firewall products that focus on protecting against network level
attacks, or pure Intrusion Prevention Systems that focus on preventing ever
increasing quantities of known attacks, the TrafficShield product allows
organizations to easily define what "good traffic" is and apply policies to only
allow desired traffic through to web servers and applications. It offers
organizations a Web application infrastructure protection system capable of
blocking a broad range of network, web infrastructure and web application
attacks to enable maximum business-critical transaction throughput at all times.

      "F5 owns a strategic piece of real estate in the network that sits
directly in front of applications and servers, making F5's Application Traffic
Management and MagniFire's products an elegant and unmatched solution for
application security," said Eitan Bauch, CEO of MagniFire. "F5 is a trusted name
in application networking and has a strong track record of leading the market
with timely innovations. I'm confident that the combined strength of our people,
technologies and products will deliver immediate benefits to the market, while
laying a robust and resilient foundation for future needs."

      In order to induce MagniFire employees to continue their employment
following the acquisition, F5 will issue options to acquire up to an aggregate
of 415,000 shares of common stock to approximately 20 non-officer MagniFire
employees. These options will be granted without shareholder approval pursuant
to Nasdaq Marketplace Rule 4350 (i)(1)(A)(iv) with the following general terms;
each option will have an exercise price equal to fair market value on the grant
date, have a ten-year term, and vest over a four year period.

      Further details about the MagniFire WebSystems acquisition will be
discussed in a conference call tomorrow, June 2 at 8:00 a.m. E.T. Call-in
numbers: 1-888-323-2712 (US and Canada) and 773-756-4700 (international);
conference ID: F5 Call. To listen to the webcast, go to



http://www.f5.com/f5/ir/calendar.html and click on the webcast image. A slide
presentation designed to accompany the discussion of the MagniFire acquisition
is available for public viewing at http://www.f5.com/magnifire/announcement/.

ABOUT F5 NETWORKS

F5 enables organizations to successfully deliver business-critical applications
and gives them the greatest level of agility to stay ahead of growing business
demands. As the pioneer and global leader in Application Traffic Management, F5
continues to lead the industry by driving more intelligence into network to
deliver advanced application agility. F5 products ensure the secure and
optimized delivery of applications to any user - anywhere. Through its flexible
and cohesive architecture, F5 delivers unmatched value by dramatically improving
the way organizations serve their employees, customers and constituents, while
lowering operational costs. Over 6,000 organizations and service providers
worldwide trust F5 to keep their businesses running. The company is
headquartered in Seattle, Washington with offices worldwide. For more
information go to www.f5.com.

All brands, names, or trademarks mentioned in this document are the property of
their respective owners.

This press release may contain forward looking statements relating to future
events or future financial performance that involve risks and uncertainties.
Such statements can be identified by terminology such as "may," "will,"
"should," "expects," "plans," "anticipates," "believes," "estimates,"
"predicts", "potential" or "continue" or the negative of such terms or
comparable terms. These statements are only predictions and actual results could
differ materially from those anticipated in these statements based upon a number
of factors including those identified in the Company's filings with the SEC.

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