Stopping the Spam Tsunami The Battle for the Inbox Wayne Kawamoto
The Battle for the Inbox
As in the fight against computer viruses, an entire industry has sprung up to deal with unwanted e-mail. The trick for small businesses is to find a method that requires minimal administration and accurately identifies and removes spam, but doesn't block legitimate e-mail.
Antispam products rely on three techniques to reduce the volume of unwanted e-mail. The most common method involves software and appliances that scan and compare the contents of incoming e-mail (subject, sender, and body text) to known spam characteristics and user-defined settings and criteria, then route the spam to a special folder.
One well-known scanner is the Spam Alert feature in Symantec's Norton Internet Security. Other scanning solutions include those in McAfee SpamKiller; Stata Labs' Saproxy Pro 2.5, which works with the company's Bloomba e-mail client; MailWasher; and others.
Besides scanning, McAfee SpamKiller blocks the addresses of known spammers and creates and manages a list of "friends" so messages from known sources aren't interpreted as spam. MailWasher creates a blacklist to watch for returning e-mail; recognizes friendly addresses; can refer to external blacklists such as SpamCop; and bounces e-mail back to spammers to make it appear that your e-mail address is invalid. Trend Micro's Spam Prevention Solution, a part of the company's InterScan Messaging Security Suite, protects an enterprise at the gateway, offers policy-based configuration options, and creates approved-sender lists both at the gateway and mail server.
A second method relies on third-party mail servers that filter e-mail before it reaches a business. These systems create and maintain lists of IP addresses that are known to send spam, and filter e-mail from these sources.
In this category, Cloudmark's SpamNet generates a signature from an incoming message and consults a database to determine if the e-mail is spam. When users encounter new spammers, they may easily add them to the database for future alerts. Nemx's Power Tools for Exchange, which supports Microsoft Exchange Server, also consults a database of addresses that are known to serve spam and offers scanning functions.
A third method creates what's known as a whitelist of approved senders who are free to communicate with you, blocking messages from all other, unapproved correspondents. The process of creating an account with Mailblocks, for example, imports addresses from your existing inbox and other mail folders. Suspected spam is listed in one place while messages from approved senders appear in another. MailFrontier Enterprise Gateway generates whitelists and relies on some 200,000 rules to detect and block spam.
