In practice, however, filters suffer from significant error rates, particularly false negatives, relegating legitimate email into the Junk mailbox. Sophisticated solutions like SpamAssassin use Bayesian filters, which are self-learning text filters that cull junk email on the basis of content – in theory, at least. You can come to grips with unwanted advertising email using a complex set of rules. Statistical tests and URL block lists are also used for spam detection and subsequent processing.įigure 1: SpamAssassin uses a variety of databases for analyzing and assessing email. A content filter checks the header and body content. Black and white lists explicitly exclude or include email addresses.

Intelligent spam filters like SpamAssassin employ various solutions ( Figure 1). Ideally, the filter should be located in the enterprise at the central node through which incoming email traffic runs and where the most efficient filtering is possible. Much like antivirus programs, spam protection needs to be updated continually if it is to provide protection. You can get the flood of advertising email under control to a certain degree with the use of spam filters. Spam is a dynamic, not a static, problem, and spammers usually respond very quickly and cleverly to countermeasures of any kind.

The proportion of email advertising messages can be greater than 50 percent, forcing employees to check every piece of email and manually dump at least every second message in the Trash. Spam in your Inbox at home is a nuisance you can hardly avoid, but what is merely irritating at home is a genuine problem in the business world.

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