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 e-mail program. They are also built into or added onto a mail server, in which case the spam never reaches the user's mailbox. See e-mail program and mail server.

Spam filtering can be configured to trap messages based on a variety of criteria, including sender's e-mail 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 e-mail 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 ?
As my PhD student, Lynam made fundamental contributions to spam filtering and spam filter evaluation, resulting in a dramatic improvement in state of the art spam filter technologies, demonstrated by sound scientific measurement," said G.
The nTelligent Spam Filter can be managed by HyperNet and it is possible to install the product on a corporate network in less than five minutes, according to the company.
SEM is powered by the award-winning spam filter, SPAMfighter.
SPAMfighter was tested in a spam filter round-up which included Goto Software Vade Retro, Kaspersky Internet Security, McAfee Internet Security, Spamihilator, and BitDefender Internet Security 2008.
The spam filter is based on open source systems and uses spam blacklists to block unwanted marketing messages arriving in a user's inbox.
Taking a multi-layered approach, PineApp's anti spam appliance employs an email spam filter based on 11 detection engines resulting in a detection ratio of more than 98% and a false-positives rate of less than 1%.
The SpamExam report also includes spam filter results, a blacklist monitor, a validation component which identifies poorly coded HTML, and recommendations for e-mail content and copy changes.
Spam filters help reduce the number of phishing e-mails you get, while firewalls can prevent unauthorized entry and hacking into your computer.