spam filter


Also found in: Dictionary, Thesaurus, Medical, Legal, Financial, Wikipedia.

spam filter

A software routine that deletes incoming spam or diverts it to a "junk" mailbox (see spam folder). Also called "spam blockers," spam filters are built into a user's email program. They are also built into or added onto a mail server, in which case the spam never reaches the user's mailbox. See email program and mail server.

Spam filtering can be configured to trap messages based on a variety of criteria, including sender's email address, specific words in the subject or message body or by the type of attachment that accompanies the message.

Blacklists and Whitelists
Address lists of habitual spammers, known as "blacklists," are continuously updated by various organizations and ISPs. Mail from blacklist addresses is rejected at the mail server. See Blacklist of Internet Advertisers.

The opposite approach is taken to ensure that bona fide mail is not automatically rejected. Users or network administrators can create a list of allowed email addresses, known as a "whitelist," and the mail client or mail server will always accept mail from whitelist addresses. Mail client software typically treats the user's address book as a whitelist, presuming that mail coming from an address maintained by the user is always valid.

Analyze the Content
In order to more effectively analyze the content and not trash a real message, sophisticated spam filters use artificial intelligence (AI) techniques that look for key words and attempt to decipher their meaning in sentences (see Bayesian filtering). See spam trap, spam relay and spamdexing. See also ad blocker and popup blocker.
References in periodicals archive ?
SPAMfighter is a community-based spam filter, which enables users to report any spam mail slipping past the SPAMfighter filter, to the server.
THE E-MAIL MARKETING COMMUNITY is still quaking over recently announced plans by America Online and Yahoo to begin charging internet postage for optional "preferred e-mail" service, which would enable company e-mails to breeze past the spam filters of the two e-mail service providers.
Wide agreement on the need to check messages for signs of forgery is a key step toward eliminating a favorite spammers' trick--one used to defeat spam filters and entice unwary recipients into opening attachments that may contain harmful worms and viruses.
If your spam filter flagged it, changes are the spam filters used by others will do so as well.
SPAMfighter is Europe's leading spam filter developer.
A researcher on the reproductive activities of fruit flies could find e-mail blocked because the spam filter cannot differentiate it from the flood of sex-related information figuring in message scans.
HyperNet Inc, a subsidiary of Prospectus Group, has begun offering its nTelligent Spam Filter for companies wishing to reduce the level of spam and viruses received.
SPAMfighter Has Released a Version of the Award-Winning Spam Filter for Microsoft Exchange for Windows Server 2008