Symantec has released the latest version of its e-mail security gateway.

Mail Security for SMTP 4.0 offers new features for cleaning up after mass-mailing worms and identifying trusted mail domains, as well as improved capabilities for detecting spam.

Formerly called Symantec Antivirus for SMTP Gateways 3.1, Symantec Mail Security combines anti-virus, e-mail content filtering and spam prevention. It scans e-mail at the SMTP gateway before it reaches a company's mail server or user inboxes.

A new feature in Version 4.0 automatically collects and monitors so-called "trusted" Internet domains from which e-mail messages should be accepted without having to pass through the product's heuristic spam filters and blacklists of banned domains. The feature will reduce false positives, in which legitimate e-mail correspondence is flagged as spam, Symantec said.

The new Mass Mailer Cleanup feature helps companies eliminate the flood of e-mail traffic generated by mass mailing worms such as NetSky and Mydoom. Many gateway anti-virus products strip out virus-tinged e-mail file attachments or quarantine the e-mail message. However, Mail Security for SMTP 4.0 deletes the entire message and its attachment, reducing the amount of virus-generated e-mail that ends up on mail systems, Symantec said.

Other new features include the ability to customise spam filtering rules that look for specific text or keywords, as well as undesirable or offensive language and message content. Customers will also now be able to insert custom text, including legal disclaimers, to outgoing mail messages, Symantec said.

The software is available from today. Pricing starts at $15 per user for licenses of 10 to 25 users. For a 2,000 user license, the cost is around $10 per user, according to a company spokesman.