Tumbleweed Introduces Tumbleweed Web Filter v5.0 Extending Security to Enterprise Web Usage

REDWOOD CITY, CA - June 5, 2001 - Tumbleweed® Communications Corp. (Nasdaq:TMWD), a leading provider of mission-critical messaging software, today announced the launch of Tumbleweed Web Filter(tm) v5.0, the latest product release in Tumbleweed's family of messaging management solutions. With its messaging management solutions, Tumbleweed provides a comprehensive range of security tools for businesses to centrally manage and set policy for both email and Web communications.

Tumbleweed Web Filter 5.0 empowers IT managers to apply multiple security countermeasures to web-based communications coming into and going out of their organizations, allowing for security and management to extend beyond the traditional firewall to enterprise web usage. Web Filter 5.0 complements the capabilities of Tumbleweed Messaging Management System™ (MMS™), which enables businesses to apply policies at the server level to enterprise-wide email for content control, encryption, access control, attachment management, virus scanning, as well as digital signatures. Using both MMS and Web Filter, organizations can centrally set automated policies to manage all aspects of Internet communication, from email (SMTP protocol) to browser-based communications and web usage (HTTP protocol).

"As a current customer using Tumbleweed MMS, we're pleased that Tumbleweed now offers an integrated solution that extends policy enforcement and virus protection to enterprise Web usage," said Gary Mattson, Senior Enterprise Network Management, Security and Encryption Engineer, Catholic Healthcare West. "Since MMS and Web Filter are both proxy-independent, together they offer complete policy-management that can be easily implemented across distributed geographic locations without replacing existing infrastructure."

A key new feature of Web Filter 5.0 is that it can be deployed using its own proxy authentication front-end so it works seamlessly with pre-existing cache and firewall installations. With its security countermeasures, Web Filter 5.0 improves network performance by protecting enterprise environments from Web-based malicious mobile code, viruses and large file download that can cause high bandwidth consumption. Content and access control features allow managers to block employee use of unauthorized Web-based email software, message boards or URL sites at the corporate, division, work group or individual level.

"Corporations are increasingly concerned with uncontrolled Internet access because it can lead to compromised network performance, high bandwidth consumption, exposure to viruses and malicious mobile code, as well as lost productivity and legal risks," said Christian A. Christiansen, Vice President, IDC. "We believe that Internet access control is a major element in enterprise security architectures. The market for solutions such as Tumbleweed Web Filter is expected to grow to approximately $636 million by 2004."

Tumbleweed will be holding a web seminar for customers on June 7, 2001 to review recently released new products. During the seminar, the features and benefits of Tumbleweed Web Filter 5.0 will be discussed. To access the seminar, visit Tumbleweed's website at www.tumbleweed.com and go to the events section.

About Tumbleweed
Tumbleweed Communications (NASDAQ:TMWD) is a leading provider of mission critical messaging software that enables organizations to manage and secure online business communications and processes. Tumbleweed's customers use the company's solutions to define secure communication networks, to centrally control and monitor the corporate communications stream and to create a foundation for automated preparation and secure Internet delivery of sensitive business information. Companies that rely on Tumbleweed Communications solutions include American Express, Chase Manhattan Bank, Chevron, Datek Online, the European Union's Joint Research Council, FDA, John Deere, Merrill Lynch, Nike, Northern Trust, NTT, Salomon Smith Barney, Travelers, United Parcel Service, and seven of the world's largest postal services. Tumbleweed Communications was founded in 1993 and is headquartered in Redwood City, CA. More information can be found at www.tumbleweed.com.

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.