Portal de Periódicos da CAPES

Controlling spam with SpamAssassin

2007; Belltown Media; Volume: 2007; Issue: 153 Linguagem: Inglês

1938-3827

Colin McGregor,

Spam and Phishing Detection

How to set up SpamAssassin and teach it to recognize spam. The people who produce unsolicited commercial e-mail (UCE), or spam, are the big thieves of the Information Age, spewing out messages for pharmaceuticals, time pieces, fast money and fast women. Large chunks of bandwidth that we have to pay for is eaten up by these crooks. After getting these messages, we have to waste time going through our inboxes and deleting the garbage. Further, unlike magazines, newspapers, commercial radio and television, where the advertisements reduce the cost or make the content free, spam gives nothing back to us as readers or viewers. Although we cannot stop spam, some tools exist to make spam easier to deal with. One such tool is SpamAssassin, which looks at each incoming e-mail message and rates the probability that the e-mail is spam. Messages that are given a high probability of being spam get flagged as such, and other programs, such as Evolution, KMail or Procmail, can deal painlessly with the flagged e-mail. SpamAssassin works by going through e-mail messages and looking for things that are associated with spam or non-spam e-mail, which add or subtract points from an e-mail's score. So, for example, the word Viagra, and close misspellings of Viagra (as they are used in many pharmaceutical spam messages), adds to the total score. On the other hand, a valid Sender Policy Framework (SPF) record in the e-mail, which shows that the sender location was not forged, subtracts from the score. By default, any message that gets a total score of five or more is assumed to be spam. One problem with the above calculations is that it is a fair bit of work for your computer, so if your machine is currently straining under the workload it has, or if you deal with a lot of e-mail, you may want to look at a hardware upgrade (faster CPU chip and/or more memory) before starting up SpamAssassin. A number of Linux distributions include SpamAssassin by default. If yours isn't one of them, it should be very simple to add. If you have a Debian-based distribution, it should be as simple as starting up a terminal window and typing: sudo apt-get install spamassassin Once installed, you can start tweaking SpamAssassin's settings. SpamAssassin's configuration file can be found at ~/.spamassassin/user_prefs. The first setting is required_score: