Tumbleweed Releases E-Mail Firewall Appliance For Fighting Spam

New Tumbleweed MMS Appliance Integrates Dynamic Anti-spam Service IntoLeading Enterprise E-Mail Firewall, Priced For Mid-Sized CompaniesRedwood City, CA – July 15, 2003 – Tumbleweed® Communications Corp.(NASDAQ:TMWD), a leading provider of mission-critical Internetcommunications software for business and government, today announced a newe-mail firewall appliance for fighting spam. Tumbleweed MMS – ApplianceEditionâ„?, the industry’s only Windows-based e-mail firewall appliance, nowintegrates Tumbleweed’s Dynamic Anti-spam Service, bringing the full powerof 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 capabilitiesenjoyed by Tumbleweed’s Fortune 500 customers.

Tumbleweed MMS – Appliance Edition provides mid-sized companies with aturnkey e-mail firewall solution that delivers the industry’s fastest “timeto protection.” By significantly easing the procurement and installationchallenges associated with deploying an enterprise-class e-mail firewall,the completely integrated solution also greatly reduces ongoing maintenancerequirements, 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 1Uchassis. All of the software components come pre-installed andpre-configured, including the MMS 5.5 software, Dynamic Anti-spam Service,and the Windows 2000 operating system and SQL Server 2000 database (bothhardened with the latest security updates). An integrated update serviceallows administrators to automatically download and install patches andupdates to the MMS Appliance.

About Tumbleweed’s Dynamic Anti-Spam Service:
The Tumbleweed Dynamic Anti-spam Service includes a highly effective SpamAnalysis Engine, which automates the identification of spam using powerfulheuristics-based analysis; typical customers see an immediate 90%+ capturerate with one-tenth of one percent false positive rate before tuning. TheDynamic Anti-spam Service is an Internet-based subscription service, similarto the way anti-virus products work, which dynamically updates the SpamAnalysis 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 newspammer trends and tactics, and create and publish new heuristics to stopthem. The Lab analyzes both spam and legitimate e-mail gatheredinternationally and provided by enterprise customers, to ensure that theDynamic Anti-spam Service minimizes false positives in a businessenvironment.

Tumbleweed’s Dynamic Anti-spam Service automatically refreshes the appliancewith the latest spam fighting updates. “We’re amazed at the effectiveness ofTumbleweed’s Dynamic Anti-spam Service,” said Conal Gallagher, Director ofSystems, InstallShield Software Corporation. “It does an incredible jobfiltering out the spam coming in to our company. In fact, when we firststarted using it, our mail flow went down so much, I worried the e-mailservers might have gone down. Instead, it was just that the spam had goneaway.”

About Tumbleweed’s MMS e-Mail Firewall:
Tumbleweed’s MMS e-mail firewall is rated by Information Security Magazineas the #1 e-mail firewall software for large enterprises, and is currentlyin use at over 400 of the largest, most demanding messaging infrastructuresin the world. The new MMS e-mail firewall appliance offers the sameenterprise level protection and management capabilities to mid-sizedcompanies: combining a multi-layer spam defense, virus scanning, inbound andoutbound content filtering, e-mail encryption, regulatory compliance (SEC,NASD, HIPAA, GLB, FDA), and e-mail policy enforcement into a single systemwith a single point of management, providing a highly scalable, low-latencyinfrastructure for all e-mail hygiene functions.

“The deluge of unwanted junk e-mail has reached epic proportions, and thetypes of spam are changing daily,” said Dave Jevans, Tumbleweed’s SeniorVice President of Marketing. “Tumbleweed’s new e-mail firewall appliancewith the Dynamic Anti-spam Service now gives every company a powerful andcost-effective defense against spam and viruses that, until now, could onlybe 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 canbe blocked, but an e-mail firewall that includes an anti-spam engineprovides the best approach for enterprises looking to stop spam. There areseveral reasons for this:

* Perimeter defense is best – spam enters the organization from theInternet. An e-mail firewall sits at the perimeter of the network betweenthe Internet and corporate e-mail servers, controlling this single point ofentry for spam.
* Integrated hacker protection – because e-mail firewalls include anintegrated e-mail relay, they can incorporate e-mail hacker protectionagainst Directory Harvest attacks, Denial-of-Service attacks, and hijackingof open relays by spammers.
* Tuning/customization – e-mail firewalls can generally filter e-mailbased on both the message content and the identity of the sender andrecipient. This provides powerful capabilities to fine-tune the definitionof spam to match the needs of the enterprise.
* Lower total cost of ownership (TCO) – Most organizations have a numberof point applications sitting in their mission-critical e-mail stream,potentially including anti-virus, content filtering, archiving, and/orencrypted e-mail applications. An e-mail firewall allows an organization toconsolidate their anti-spam solution with all of these other applicationsinto a single, affordable, scalable perimeter defense product that providescentralized management, control and reporting, and reduces software licensecosts, downtime and administration.

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

“The increasing volumes of critical business data contained in e-mail, thelevel of threat to the organization, and the relationships maintained withcustomers through e-mail channels now necessitate that organizations lookfor more reliable, scalable, and cost effective mechanisms to manage e-mailhygiene and security,” said Matt Cain, Vice President of the META Group.”E-mail firewall solutions today provide spam management, protection fromviruses and hacker threats, e-mail compliance with corporate policies andgovernment regulations, e-mail encryption capabilities, and the ability tointelligently filter and archive e-mail to match enterprise retentionpolicies. Organizations should plan on tripling or quadrupling the capitalresources devoted to such systems.”

About Tumbleweed Communications Corp.
Tumbleweed is a leading provider of mission-critical Internet communicationssoftware products for enterprise and government. By making Internetcommunications secure, reliable and automated, Tumbleweed’s email firewall,secure file transfer, secure email, and identity validation solutions helpcustomers significantly reduce the cost of doing business. Tumbleweedprovides services for over 600 customers, including ABN Amro, CatholicHealthcare West, Bank of America Securities, JP Morgan Chase & Co., TheRegence Group (Blue Cross/Blue Shield), Society for Worldwide InterbankFinancial 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 inRedwood City, California. For additional information about Tumbleweed go towww.tumbleweed.com or call 650-216-2000.

SAFE HARBOR STATEMENT

Tumbleweed cautions that forward-looking statements contained in this pressrelease are based on current plans and expectations, and that a number offactors could cause the actual results to differ materially from theguidance given at this time. These factors are described in the Safe Harborstatement below.

Except for the historical information contained herein, the mattersdiscussed in this press release may constitute forward-looking statementsthat involve risks and uncertainties that could cause actual results todiffer materially from those projected, particularly with respect to thecharacteristics and effectiveness of Tumbleweed’s products and services, aswell 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. Forfurther cautions about the risks of investing in Tumbleweed, we refer you tothe documents Tumbleweed files from time to time with the Securities andExchange Commission, particularly Tumbleweed’s Annual Report on Form 10-Kfiled June 4, 2003, and the registration statement on Form S-4 filed June 2,2003.

Tumbleweed assumes no obligation to update information contained in thispress release, which represents the Company’s expectations only as of thedate of this release and should not be viewed as a statement about theCompany’s expectations after such date. Although this release may remainavailable on the Company’s website or elsewhere, its continued availabilitydoes not indicate that the Company is reaffirming or confirming any of theinformation contained herein.