POSTINI BLOCKING 53 PERCENT OF EMAIL CONNECTIONS WITHOUT THE NEED TO SCAN CONTENT OF MESSAGES

Postini Reports That the Spam War Is Changing From a Content Filtering Battle to a Connection Management Battle

REDWOOD CITY, CA, July 7, 2004 - Reporting that the spam war is changing from a content filtering battle to a real time SMTP connection management battle, Postini, the industry's leading provider of email security and management for the enterprise, today announced that it is currently blocking 53 percent of all email connections without having to read message content. Postini can block the majority of malicious email traffic based on the real time behavior of the spammers' IP addresses which cannot be spoofed the way messages can.

"The spam story today is one of connections, not content," said Scott Petry, Postini founder and senior vice president of products and engineering. "Spam content has been changing yet again during the last six months, making it far harder for content filters to detect. The key to defending against spam is to move up the Simple Mail Transfer Protocol (SMTP) connection."

Petry added that the most successful email protection is to get as close as possible to the spammer. "Since we can't get behind their firewalls, the best thing we can do is watch the spammer's behavior at the connection layer and preemptively shut them down before they do any harm. Only Postini is positioned to protect at this level."

During the month of June, Postini received 10.75 billion SMTP requests, blocking 53 percent of those requests based on the IP address of the sender. Of the 10.75 billion SMTP connections received, only 11 percent were legitimate email. Of the remaining 47 percent, or 5.7 billion messages Postini scanned for content, spam accounted for approximately 76 percent. Postini also stopped a total of 110 million virus instances from entering corporate networks, an increase of 1.7 percent from last month.

Postini also announced that in June it protected customers from over 16 million directory harvest attacks (DHAs), an increase of 5.4 percent since May. Postini registered over 3.2 billion invalid delivery attempts for the month.

According to Postini, the top-ten viruses of June were:

Virus Name	Quantity Detected
1. netsky	49,737,325
2. zafi	21,676,180
3. mime	16,415,611
4. objectdata	7,341,821
5. sober	6,797,741
6. bagle	3,358,045
7. lovgate	1,404,237
8. klez	720,899
9. mydoom	671,459
10. dumaru	608,592

Postini's managed services model uses patented Preemptive Email Protection technology to protect enterprise servers and desktops at the perimeter, stopping spam and viruses before they enter the network. The solution handles enterprise email system security and management, offering spam and virus filtering, content and policy management, disaster recovery, industry specific content filtering, and protection from email attacks such as directory harvest attacks and email denial of service attacks. Postini processes approximately 1.4 billion messages each week through its array of distributed data centers, over five times more than any other email security services provider, making Postini the fourth-largest email system in the world.

About Postini
Postini, Inc. is the industry's leading provider of email security and management solutions that protect email communications infrastructure by preventing spam and attacks from reaching the enterprise gateway. Postini's patented managed services model utilizes exclusive preEMPTä transport and content filtering technology to eliminate spam and viruses, stop DoS and directory harvest attacks, safeguard content, and improve email performance. Founded in 1999, Postini processes more than one billion email messages every week for more than 3,300 companies. By blocking spam, viruses and attacks before they can reach the enterprise email gateway, Postini Perimeter Manager assures complete email security while saving bandwidth, conserving server capacity and minimizing administrative costs. For more information contact Postini at its Redwood City, California headquarters toll-free at 866.767.8461, or visit www.postini.com.

Postini is a registered trademark of Postini, Inc.

Marty Tacktill
Public Relations Manager
650.482.3197
650.482.3109 FAX
marty@postini.com

Bryan Ferraro
Neale-May & Partners
650.328.5555 ext. 277
bferraro@nealemay.com

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