Spam Blocker

What Does Spam Blocker Mean?

A spam blocker is a special kind of software, software extension or even a simple technique that is designed to block unsolicited bulk emails, or spam. Spam messages are sent by unsolicited advertisers in bulk to email users.


Because many types of spam blockers are simply modified filters, a spam blocker also may be known as a spam filter.

Techopedia Explains Spam Blocker

Some spam blockers are real programs, although small, while some are simply custom configurations in an email client’s filter function that check for certain keywords in the subject line of messages. This type of spam blocker has many limitations. Spam messages that get through the spam blocker are called false negatives, while legitimate emails that are blocked are called false positives.

Spam blockers and filters have lists that contain address that are either allowed to pass through or blocked. Addresses that are allowed to pass are placed on the "white list," while those that are supposed to be blocked are placed in the "black list."


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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.