Tumbleweed to Provide Secure Content Management and Support For Siebel 7

Secure Guardian and Siebel 7 complement each other to provide the most secure eBusiness Application for internal, customer and partner communications

REDWOOD CITY, CA - October 2, 2001 - Tumbleweed® Communications Corp. (Nasdaq:TMWD), a leading provider of secure content management solutions for enabling the business Internet, announced today the support for Siebel 7, the seventh major release of Siebel eBusiness Applications from Siebel Systems Inc., (Nasdaq: SEBL), the world's leading provider of eBusiness applications software. Tumbleweed's Secure Messenger solution will be validated with Siebel 7 within the first 90 days of Siebel 7 general availability, providing organizations with complete eBusiness solutions that increase productivity, maximize revenue and profit, and significantly enhance customer acquisition, satisfaction, and retention.

Siebel Systems enables software vendors to easily integrate solutions through its open, extensible, advanced Smart Web Architecture. Unlike rudimentary HTML clients, Siebel Smart Web Architecture combines a zero-footprint, browser-based Web client and a user interface with levels of interactivity and usability traditionally available only in Windows applications. The Siebel Smart Web Architecture enables organizations to leverage the industry's best eBusiness applications at the lowest total cost of ownership.

Siebel 7 extends the reach and functionality of Siebel Systems' industry-leading suite of integrated, multichannel eBusiness applications, enabling organizations to translate customer relationship strategy into execution by effectively aligning and rapidly integrating channels, employees and partners. Siebel 7 allows organizations to manage, synchronize and coordinate all customer touch points across the Web, call center, field sales and service personnel, and partner channels.

About Tumbleweed Secure Guardian
Tumbleweed's Secure Guardian framework allows companies to communicate securely with customers, partners and suppliers over the Internet. Tumbleweed Secure Messenger and Tumbleweed Secure Mail are solutions that enable universal two-way security and audit trail capabilities for business critical messages, and content security and policy management for Internet email and groupware applications. These solutions add the critical layer of content-focused security management that increases overall customer service including customer loyalty and satisfaction.

Tumbleweed and Siebel Systems formed a strategic alliance in 2000 to integrate the market's most comprehensive email response management system, Siebel eMail Response, with Tumbleweed's secure platform. Tumbleweed's Secure Messenger provides a full, secure email communication solution to complement Siebel eMail Response. The combined solution will enhance customer acquisition, satisfaction and retention by providing a complete messaging solution that allows Siebel eBusiness Applications users across all sales, marketing and service communications channels to communicate securely and effectively.

"Tumbleweed has partnered with Siebel Systems to provide customers with a complete, best-in-breed secure eBusiness solution that will enhance customer relationship management," said Bill Bradford, Vice President of Corporate Development at Tumbleweed. "The combined Tumbleweed and Siebel 7 solution will give current and future customers the level of online security needed to execute efficient and comprehensive eBusiness transactions."

"We believe that security is a critical element in successful online customer service," said Catherine Cherubino, Senior Managing Director, Software and Industry Alliances for Siebel Systems. "Enterprises that communicate with their customers via a secure online channel demonstrate the respect they have for customer data and for customer relationships. Tumbleweed Communications has developed significant expertise in building and deploying secure communications channels that enterprises use daily to reach out to customers. The integration of Tumbleweed solutions with Siebel eBusiness Applications enables organizations of all sizes to measurably increase customer satisfaction, resulting in greater revenue and profitability."

About Siebel Systems
Siebel Systems, Inc. (Nasdaq: SEBL) is the world's leading provider of eBusiness applications software. Siebel Systems provides an integrated family of eBusiness applications software, enabling multichannel sales, marketing, and customer service systems to be deployed over the Web, call centers, field, reseller channels, retail, and dealer networks. Siebel Systems' sales and service facilities are located in more than 37 countries. For more information, please visit Siebel Systems' Web site at www.siebel.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 the security features of Tumbleweed's products and the activities of any third party. 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, 2001 and Form 10-Q filed November 13, 2001. Tumbleweed assumes no obligation to update information contained in this press release.