CUPERTINO, CALIF. - Symantec this week will join the growing lineup of vendors trying to stem the flow of junk e-mail when it releases Symantec Antivirus for SMTP Gateway Version 3.1.

Symantec has added a way to set up a so-called blacklist in Antivirus for SMTP Gateway to block mail from known spam sources and e-mail relays, as well as a whitelist of trustworthy e-mail domains that don't require filtering. Symantec's venture into spam control mirrors that of its main antivirus competitors, Network Associates and Trend Micro.

Symantec is developing its antispam technology in-house, while Trend Micro has licensed gateway technology from spam-filtering service Postini (see story). Network Associates bought antispam software vendor Deersoft with the intention of offering desktop antispam protection and gateway appliances later this year (see story).

Heuristics approach

Antispam filtering in Antivirus for SMTP Gateway uses the same kind of heuristics investigative approach, based on pattern-matching, that Symantec uses. This approach helps catch a new virus before a signature update is available, says Chris Miller, Symantec product manager. This approach isn't perfect, and there is a risk of legitimate e-mail being mistaken for spam and blocked, but Symantec says such error rates are acceptably low.

One beta tester agrees.

"We do get false positives using the Symantec heuristics, but it's less than 1%," says Brett Roquemore, senior LAN administrator at Ferguson Enterprises, a Newport News, Va., distributor of plumbing and air conditioning equipment.

Symantec's spam filter in Antivirus for SMTP Gateway also supports the use of 125 third-party antispam lists of known spammers or spam relays.

The Symantec spam filter, which costs $10 for each user for 200 users or more, and as much as $15 for less than 25, directs suspected spam into a separate mailbox. At Ferguson Enterprises, that mail is checked each day to see if anything that looks legitimate somehow got pulled aside by mistake. Spam now accounts for close to 50% of the mail traffic at Ferguson, and typically 80% on weekends.