Slicing Up Spam

John R. S. Mascio

Friday, August 15th, 2003

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1. I’m sick of spam! How can I get rid of it?

One popular method for filtering unsolicited commercial email, or spam, is SpamAssassin (http://www.spamassassin.org). SpamAssassin is a rule-based, mail filtering program that identifies spam. By itself, or combined with Razor (http:// razor.sourceforge.net), a collaborative spam-tracking database, SpamAssassin can effectively eliminate spam from your daily doses of email.

SpamAssassin is written in Perl, so the initial installation of SpamAssassin is as simple as installing a new Perl module from the Comprehensive Perl Archive Network (CPAN). As root, run the following commands (shown in bold):

 # perl -MCPAN -e shell cpan> o conf prerequisites_policy ask cpan> install Mail::SpamAssassin cpan> quit 

According to the install document, “Perl 5.8 now uses Unicode internally by default, which causes trouble for SpamAssassin (and almost all other reasonably complex pieces of Perl code!)” So, if you’re using Red Hat, you should set the LANG environment variable to “U.S. English” (i.e., export LANG=en_US) before SpamAssassin is invoked.

Once SpamAssassin is installed, you can use it in one of two ways: through procmail, or as part of a mail transport agent (MTA) such as sendmail, postfix, or qmail. Let’s focus on the first choice. (Read the SpamAssassin documentation for help with MTAs.)

Because SpamAssassin is written in Perl, launching it each time that it’s needed can be very costly, especially if an individual or a system receives large amounts of email. For higher-volume traffic, it’s recommended that you use…

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