Mission Critical Systems and Tumbleweed Partner for Secure Content Management Solutions

FORT LAUDERDALE, Fla. - January 14, 2002 - Mission Critical Systems, an award winning network security company, and Tumbleweed® Communications Corp. (Nasdaq:TMWD), a leading provider of secure content management solutions for enabling the business Internet, today announced that Mission Critical Systems has joined the Tumbleweed Channel Alliance Program. Mission Critical Systems will offer Tumbleweed's secure content management solutions that both protect and extend the enterprise network, throughout the Southeast United States.

Mission Critical Systems' focus and expertise on network security provides Fortune 500 companies and government agencies with the tools, controls and training to secure an organization's network. Mission Critical Systems' enterprise customers will benefit from the Mission Critical and Tumbleweed partnership with increased network security, enhanced employee productivity, reduced liability and optimal bandwidth.

"Email has evolved into a business-critical tool and so too has its security risks. Not only do customers need to mitigate risks such as loss or interception of sensitive data but they also must impose policies to cover legal, financial as well as damage to reputation due to the misuse of email,'' said Frank Darden, CTO, Mission Critical Systems. ``Tumbleweed's solutions meet our customer's security requirements with a strong combination of security and scalability to reduce liability and manage how business-critical information is delivered."

"Tumbleweed is pleased that Mission Critical Systems has chosen to be a Tumbleweed Channel Alliance Partner and will be able to offer customers policy-based security solutions,'' said Robert Krauss, Vice President, Channel Development at Tumbleweed. ``Tumbleweed's solutions will allow Mission Critical Systems to offer comprehensive secure content management solutions that enable companies to communicate securely with customers, partners and suppliers via the Internet."

About Mission Critical Systems, Inc.
Based in Fort Lauderdale, Florida, Mission Critical Systems is an award-winning leader in enterprise security. The company deploys best-of-breed security solutions by building strong relationships with its customers and solution partners. Since inception, Mission Critical Systems has advocated a comprehensive approach to information security. As part of its process, the company provides a detailed evaluation of all aspects of an organization's vulnerability to internal compromises and external threats. For more information on Mission Critical Systems, Inc., visit www.locked.com.

About Tumbleweed
Tumbleweed is a leading provider of solutions for managing secure communication and collaboration to enable the business Internet. Tumbleweed's robust policy-based framework empowers organizations to safely share and protect critical information, increase customer loyalty and privacy and dramatically reduce costs. Tumbleweed is trusted by 1,000 blue-chip customers including American Express, Chevron, Datek Online, the European Union's Joint Research Council, First Union Wachovia, John Deere, Merrill Lynch, Nike, Northern Trust, NTT, Salomon Smith Barney, Travelers and US Food and Drug Administration. One hundred of the Fortune 500 are Tumbleweed customers. Tumbleweed Communications was founded in 1993 and is headquartered in Redwood City, Calif., with offices around the world.

Except for the historical information contained herein, the matters discussed in this press release may constitute forward-looking statements that involve risks and uncertainties that could cause actual results to differ materially from those projected, particularly with respect to Tumbleweed's customers, products, and future offerings. In some cases, forward-looking statements can be identified by terminology such as "may," "will," "should," "potential," "continue," "expects," "anticipates," "intends," "plans," "believes," "estimates," and similar expressions. For further cautions about the risks of investing in Tumbleweed, we refer you to the documents Tumbleweed files from time to time with the Securities and Exchange Commission, particularly Tumbleweed's Form 10-K filed March 30, 2002 and Form 10-Q filed May 14, 2002. Tumbleweed assumes no obligation to update information contained in this press release.