Stomping Out Spam: The Spam Series, Part 1: Page 3
Most products being sold today bring together multiple spam-fighting technologies. "Honey pots," for instance, are e-mail addresses specifically set up to lure spammers, while "white lists," "black lists," and interfaces to spam databases can help determine which senders will be able to get their mail through to intended recipients. Widely used databases of known spammers include RBL and DUL, for instance.
Many products -- including ActiveState's PureMessage, Mirapoint's MessageDirector, and the open source program SpamAssassin -- use heuristic techniques to analyze text, SMTP headers, subject lines, embedded images, and other message components for spam characteristics. Suspected spam can either be blocked or "quarantined" (isolated from other e-mail).
Meanwhile, MailFrontier, for instance, is pioneering a technique called "e-mail challenges," which are meant to help distinguish mail sent by human beings from machine-generated spam.
"All products use more than one anti-spam technology, but no one product uses all the available technologies," says GartnerGroup's Grey.
Analysts also point to a trend toward combining anti-spam filters with antivirus and/or Web content filtering, all within the same product. SurfControl is one such example.
Solutions for Linux and Microsoft
Some anti-spam products run as gateways, while others operate at the client level, observes Michael Osterman, principal of Osterman Research. Most products are software, but some vendors -- including CipherTrust -- produce server appliance gateways.
Situated at the edge of the network, hardware gateways operate at the SMTP level, as do software gateways from companies like Trend Micro and NAI. The hardware gateways come with embedded OSes, while the software gateways run on a variety of OSes. ActiveState, for instance, recently rolled out a Linux-based gateway. All gateways, though, are "platform-agnostic" when it comes to mail exchange.
Many client-based products, on the other hand, are Microsoft-centric. Much of the anti-spam client software available today consists of Outlook plug-ins, which offer additional filtering capabilities beyond the rules built into the MS mail client.
The onslaught of spam is spawning a growing spate of solutions. In this initial article of a new three-part series on spam, we've delved into why and how spam proliferates so quickly, and we've covered the various spam-fighting solutions currently available. Later in this series, we'll drill down further into the available technologies and present some tips and strategies for choosing and implementing anti-spamware.