Tumbleweed Acquires Anti-Spam Appliance Vendor Corvigo.

Business Editors/High-Tech Writers

REDWOOD CITY, Calif.--(BUSINESS WIRE)--March 18, 2004

Addition of Reseller Channel and Top-Rated Linux Appliance

Solidifies Tumbleweed's Leadership Position in the

Email Security Market

Tumbleweed(R) Communications Corp. (Nasdaq:TMWD), a leading provider of secure Internet messaging software for enterprises today announced its acquisition of leading anti-spam appliance vendor Corvigo, Inc. By adding a hardened, secure Linux-based anti-spam appliance to its portfolio, Tumbleweed strengthens its leadership position in the anti-spam and email security markets. Tumbleweed will also accelerate its distribution plans through the addition of over twenty productive value added resellers currently selling the Corvigo appliance.

"The acquisition of Corvigo brings critical assets to Tumbleweed: a best-in-class Linux-based appliance, a growing channel of resellers, and perhaps most importantly a leading team of experts in the Linux anti-spam appliance market," said Jeff Smith, Chairman and CEO of Tumbleweed Communications.

Corvigo's Linux-based anti-spam appliance, MailGate, was rated #1 against major competitors in real-world testing by InfoWorld in February, 2004. (http://www.infoworld.com/article/04/02/13/07TCspam_1.html) Tumbleweed can now offer customers the broadest, most flexible options for stopping spam with either the MailGate hardened Linux-based appliance, or Tumbleweed's Email Firewall, a globally scalable Windows-based enterprise software solution. In addition to award winning anti-spam capabilities, Tumbleweed's Email Firewall offers an integrated set of anti-virus, intrusion detection, content filtering, email relay, encryption and authentication capabilities.

"The fastest growing segment of the anti-spam market is Linux-based appliances," said Matt Cain, Senior Vice President of META Group. "We believe that massive consolidation in the anti-spam industry is inevitable, with more than 60 small firms currently competing in the market. Companies will either acquire, get acquired, or get out of the market."

Corvigo's MailGate appliance will be sold through Tumbleweed's direct, inside and reseller sales channels in the USA and Europe. In addition Corvigo brings enhanced channel distribution from an existing, productive set of over 20 value-added resellers, and national distribution through Zones and PC Mall. And with Corvigo's Linux-based appliance, Tumbleweed will now be able to sell into new market segments that it could not previously address, including large enterprises that prefer hardened UNIX-based security solutions, and mid-tier companies desiring the simplicity of an appliance.

Corvigo's customer base includes over 100 enterprise customers including organizations such as Cox Communications Middle America, Hammacher-Schlemmer, and Purdue University. According to IDC, the appliance segment of the secure content management market is projected to grow at 70% per year through 2006.

"Corvigo's Intent-Based Filtering (IBF) artificial intelligence anti-spam engine and our Linux appliance expertise is a strong complement to Tumbleweed's Email security, anti-spam, authentication, and Email Firewall assets," said Jeff Ready, Corvigo CEO. "Moreover, we believe our growing channel of resellers is strategically significant for both the Corvigo and Tumbleweed products."

"We invested in Corvigo after we concluded that their MailGate anti-spam appliance was the most effective and easiest-to-deploy solution," said Mark Kvamme, partner at Sequoia Capital and Corvigo board member. "Combined with Tumbleweed's security expertise and marketing leadership, we feel that the Corvigo product line has the potential to dominate the anti-spam market."

Financial terms of the purchase include the issuance of approximately 4.7 million shares of Tumbleweed common stock, the assumption of approximately 400,000 stock options, and payment of $3.0 million of cash net of Corvigo's cash. Based on Tumbleweed's closing stock price on March 17, 2004, the transaction if valued at approximately $38.5 million.

"We expect there will be a positive impact on operating results in the second half of 2004 and for the year," stated Tim Conley, Tumbleweed Chief Financial Officer. Tumbleweed management will discuss additional details of the acquisition during a conference call scheduled for today, March 18, 2004, at 2:00 pm PST (5:00 pm EST).

Conference Call

The call can be accessed by dialing (800) 374-0565 in the United States, and +1 (706) 634-0820 for international callers, giving the conference name, "Tumbleweed." Participants are asked to call the assigned number approximately 10 minutes before the conference call begins. The conference call will also be available over the Internet at http://www.tumbleweed.com in the Investor section of the site. A replay of the conference call will also be available commencing two hours after the call and for the following two business days by dialing (800) 642-1687 and entering the following reservation number: 6254876. Also, a replay of the conference call will be available over the Internet at http://www.tumbleweed.com in the Investor section of the site.

About Corvigo

Corvigo is the creator of patent-pending Intent Based Filtering (IBF) artificial intelligence technology for eliminating junk email. In the overcrowded anti-spam email solution marketplace, Corvigo's unique technology has proven to be effective, easy to update, and inexpensive to maintain. IBF technology uses artificial intelligence to determine the intent of an email and then act upon that intent. Corvigo's investors include Sequoia Capital, and several other private investors.

About Tumbleweed Communications Corp.

Tumbleweed is a leading provider of secure Internet messaging software products for enterprises - both commercial 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 products are used by millions of end-users and tens of thousands of corporations. Tumbleweed customers include ABN Amro, Bank of America Securities, Catholic Healthcare West, JP Morgan Chase & Co., The Regence Group (Blue Cross/Blue Shield), NASD, 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, Calif. 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 growth of the combined Tumbleweed-Corvigo organization. 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 15, 2004.

Tumbleweed assumes no obligation to update information contained in this press release, including for example its guidance regarding its future performance, 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.