Sydney, Aust. – 29 August 2008 – Tumbleweed® Communications Corp. (NASDAQ: TMWD), an industry leader in managed file transfer and content security, today announced the incorporation of O2 Networks into its Australian channel partner program. The appointment is the latest in the expansion of the Tumbleweed Alliance Program locally and the alliance will focus on the successful implementation of Tumbleweed’s sophisticated data security and file transfer solutions with a range of O2 Networks clients.

O2 Networks is an enterprise provider of networking and security consulting services based in Sydney and Melbourne. Established in May 2002 today it supports a wide range of clients across the business spectrum. “We believe that our inclusion in the Tumbleweed Alliance Program is highly strategic both for our current client base and future business development purposes,” outlined Mr. Euan Prentice, Managing Director of O2 Networks.

“We have an in-depth understanding of the applications and processes for enhanced data security and secure file transfer for our existing clients and look forward to determining the right Tumbleweed solution for a variety of clients in various industry sectors,” he said.

Asia Pacific Partner Growth Continues

The addition of O2Networks to the Tumbleweed Alliance Program has continued the growth of the company’s premier channel alliance program in the Asia Pacific region.

According to Mr. Stree Naidu, Tumbleweed’s Regional Vice President Asia Pacific and Japan, Tumbleweed solutions are now available via a strong network of resellers, distributors and solution providers across the region.

“We are very pleased to make this announcement today welcoming O2 Networks to the Tumbleweed Alliance Program and to look forward to welcoming further clients to the Tumbleweed global network,” Naidu commented.

SAFE HARBOR STATEMENT

Tumbleweed cautions that forward-looking statements contained in this press release are based on plans and expectations as of the date of the press release, 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 Tumbleweed’s success in opening new verticals, rapidly enabling resellers, and driving significant growth and profitability for partners, as well as the continued participation of current members of the program, and the number of professionals selling Tumbleweed solutions. 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 14, 2007 and Form 10-Q filed May 10, 2007.

Tumbleweed assumes no obligation to update information contained in this press release. Although this release may remain available on Tumbleweed’s website or elsewhere, its continued availability does not indicate that Tumbleweed is reaffirming or confirming any of the information contained herein.

About Tumbleweed

Tumbleweed Communications Corp. (NASDAQ:TMWD), the industry’s leading pure play messaging security vendor, provides world-class innovative messaging security solutions for organizations of all sizes. Organizations rely on Tumbleweed's solutions to securely manage their Internet communications, spanning email management to file transfers. Tumbleweed has nearly 2,700 customers worldwide, representing industries such as Finance, Healthcare, and the U.S. Government. The world’s most security conscious organizations rely upon Tumbleweed technology including Bank of America Securities, JP Morgan Chase & Co., the U.S. Food and Drug Administration, and the U.S. Department of Defense. Our award-winning products build on fourteen years of R&D and 26 security patents in the U.S. alone – many of which are licensed by other security vendors. More information can be found at www.tumbleweed.com.

Tumbleweed is a registered trademark of Tumbleweed Communications Corp. in the United States and/or other countries. All other trademarks are the property of their respective owners.

About O2 Networks

O2 Networks is the leading Australian provider of networking and security professional services for Application Delivery Networks. O2 Networks enable clients to ensure their IT networks deliver assured and secure access to their critical business applications with optimal performance, resilience and scalability.

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