Tumbleweed Releases E-Mail Firewall Appliance for Fighting Spam.

Business Editors/High-Tech Writers

REDWOOD CITY, Calif.--(BUSINESS WIRE)--July 15, 2003

New Tumbleweed MMS(TM) Appliance Integrates Dynamic

Anti-spam Service Into Leading Enterprise E-Mail

Firewall, Priced For Mid-Sized Companies

Tumbleweed(R) Communications Corp. (Nasdaq:TMWD), a leading provider of mission-critical Internet communications software for business and government, today announced a new e-mail firewall appliance for fighting spam. Tumbleweed MMS -- Appliance Edition(TM), the industry's only Windows-based e-mail firewall appliance, now integrates Tumbleweed's Dynamic Anti-spam Service, bringing the full power of Tumbleweed's enterprise class e-mail firewall to mid-sized organizations, and providing them the same comprehensive set of anti-spam, anti-virus, e-mail policy management, e-mail encryption and e-mail relay capabilities enjoyed by Tumbleweed's Fortune 500 customers.

Tumbleweed MMS -- Appliance Edition provides mid-sized companies with a turnkey e-mail firewall solution that delivers the industry's fastest "time to protection." By significantly easing the procurement and installation challenges associated with deploying an enterprise-class e-mail firewall, the completely integrated solution also greatly reduces ongoing maintenance requirements, contributing to a much lower TCO (total cost of ownership). The MMS Appliance comes in 1-CPU or 2-CPU versions in a rack-mounted 1U chassis. All of the software components come pre-installed and pre-configured, including the MMS 5.5 software, Dynamic Anti-spam Service, and the Windows 2000 operating system and SQL Server 2000 database (both hardened with the latest security updates). An integrated update service allows administrators to automatically download and install patches and updates to the MMS Appliance.

About Tumbleweed's Dynamic Anti-Spam Service:

The Tumbleweed Dynamic Anti-spam Service includes a highly effective Spam Analysis Engine, which automates the identification of spam using powerful heuristics-based analysis; typical customers see an immediate 90%+ capture rate with one-tenth of one percent false positive rate before tuning. The Dynamic Anti-spam Service is an Internet-based subscription service, similar to the way anti-virus products work, which dynamically updates the Spam Analysis Engine with new heuristic defenses as they are published. Tumbleweed's Message Protection Lab develops and publishes these updates: the Lab is staffed by experts who continually analyze spam to identify new spammer trends and tactics, and create and publish new heuristics to stop them. The Lab analyzes both spam and legitimate e-mail gathered internationally and provided by enterprise customers, to ensure that the Dynamic Anti-spam Service minimizes false positives in a business environment.

Tumbleweed's Dynamic Anti-spam Service automatically refreshes the appliance with the latest spam fighting updates. "We're amazed at the effectiveness of Tumbleweed's Dynamic Anti-spam Service," said Conal Gallagher, Director of Systems, InstallShield Software Corporation. "It does an incredible job filtering out the spam coming in to our company. In fact, when we first started using it, our mail flow went down so much, I worried the e-mail servers might have gone down. Instead, it was just that the spam had gone away."

About Tumbleweed's MMS e-Mail Firewall:

Tumbleweed's MMS e-mail firewall is rated by Information Security Magazine as the #1 e-mail firewall software for large enterprises, and is currently in use at over 400 of the largest, most demanding messaging infrastructures in the world. The new MMS e-mail firewall appliance offers the same enterprise level protection and management capabilities to mid-sized companies: combining a multi-layer spam defense, virus scanning, inbound and outbound content filtering, e-mail encryption, regulatory compliance (SEC, NASD, HIPAA, GLB, FDA), and e-mail policy enforcement into a single system with a single point of management, providing a highly scalable, low-latency infrastructure for all e-mail hygiene functions.

"The deluge of unwanted junk e-mail has reached epic proportions, and the types of spam are changing daily," said Dave Jevans, Tumbleweed's Senior Vice President of Marketing. "Tumbleweed's new e-mail firewall appliance with the Dynamic Anti-spam Service now gives every company a powerful and cost-effective defense against spam and viruses that, until now, could only be afforded by larger companies."

An E-mail Firewall is the Best Defense Against Spam

There are a number of different places the IT infrastructure where spam can be blocked, but an e-mail firewall that includes an anti-spam engine provides the best approach for enterprises looking to stop spam. There are several reasons for this:

-- Perimeter defense is best -- spam enters the organization from

the Internet. An e-mail firewall sits at the perimeter of the

network between the Internet and corporate e-mail servers,

controlling this single point of entry for spam.

-- Integrated hacker protection -- because e-mail firewalls

include an integrated e-mail relay, they can incorporate

e-mail hacker protection against Directory Harvest attacks,

Denial-of-Service attacks, and hijacking of open relays by

spammers.

-- Tuning/customization -- e-mail firewalls can generally filter

e-mail based on both the message content and the identity of

the sender and recipient. This provides powerful capabilities

to fine-tune the definition of spam to match the needs of the

enterprise.

-- Lower total cost of ownership (TCO) -- Most organizations have

a number of point applications sitting in their

mission-critical e-mail stream, potentially including

anti-virus, content filtering, archiving, and/or encrypted

e-mail applications. An e-mail firewall allows an organization

to consolidate their anti-spam solution with all of these

other applications into a single, affordable, scalable

perimeter defense product that provides centralized

management, control and reporting, and reduces software

license costs, downtime and administration.

In general, organizations are starting to focus more resources on their e-mail infrastructure, and an e-mail firewall approach provides a reliable, scalable, and broadly functional solution to the challenge of e-mail management.

"The increasing volumes of critical business data contained in e-mail, the level of threat to the organization, and the relationships maintained with customers through e-mail channels now necessitate that organizations look for more reliable, scalable, and cost effective mechanisms to manage e-mail hygiene and security," said Matt Cain, Vice President of the META Group. "E-mail firewall solutions today provide spam management, protection from viruses and hacker threats, e-mail compliance with corporate policies and government regulations, e-mail encryption capabilities, and the ability to intelligently filter and archive e-mail to match enterprise retention policies. Organizations should plan on tripling or quadrupling the capital resources devoted to such systems."

About Tumbleweed Communications Corp.

Tumbleweed is a leading provider of mission-critical Internet communications software products for enterprise and government. By making Internet communications secure, reliable and automated, Tumbleweed's email firewall, secure file transfer, secure email, and identity validation solutions help customers significantly reduce the cost of doing business. Tumbleweed provides services for over 600 customers, including ABN Amro, Catholic Healthcare West, Bank of America Securities, JP Morgan Chase & Co., The Regence Group (Blue Cross/Blue Shield), Society for Worldwide Interbank Financial Telecommunication (SWIFT), St. Luke's Episcopal Healthcare System, the US Food and Drug Administration, and the US Navy and Marine Corps. Tumbleweed Communications was founded in 1993 and is headquartered in Redwood City, California. For additional information about Tumbleweed go to www.tumbleweed.com or call 650/216-2000.

SAFE HARBOR STATEMENT

Tumbleweed cautions that forward-looking statements contained in this press release are based on current plans and expectations, and that a number of factors could cause the actual results to differ materially from the guidance given at this time. These factors are described in the Safe Harbor statement below.

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 characteristics and effectiveness of Tumbleweed's products and services, as well as e-mail firewall architecture in general. 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 Annual Report on Form 10-K filed June 4, 2003, and the registration statement on Form S-4 filed June 2, 2003.

Tumbleweed assumes no obligation to update information contained in this press release, which represents the Company's expectations only as of the date of this release and should not be viewed as a statement about the Company's expectations after such date. Although this release may remain available on the Company's website or elsewhere, its continued availability does not indicate that the Company is reaffirming or confirming any of the information contained herein.