SpamAssassin uses header analysis, text analysis, blacklists, a spam-tracking database, andself-learning Bayesian spam analysis to quickly and accurately identify and tag spam.The easiest way for a local user to use SpamAssassin is to place the following line near the topof the ~/.procmailrc file:INCLUDERC=/etc/mail/spamassassin/spamassassin-default.rcThe /etc/mail/spamassassin/spamassassin-default.rc contains a simple Procmail rulethat activates SpamAssassin for all incoming email. If an email is determined to be spam, it istagged in the header as such and the title is prepended with the following pattern:*****SPAM*****The message body of the email is also prepended with a running tally of what elements causedit to be diagnosed as spam.To file email tagged as spam, a rule similar to the following can be used::0 Hw * ^X-Spam-Status: Yes spamThis rule files all email tagged in the header as spam into a mailbox called spam.Since SpamAssassin is a Perl script, it may be necessary on busy servers to use the binarySpamAssassin daemon (spamd) and client application (spamc). Configuring SpamAssassin thisway, however, requires root access to the host.To start the spamd daemon, type the following command as root:/sbin/service spamassassin startTo start the SpamAssassin daemon when the system is booted, use an initscript utility, such asthe Services Configuration Tool (system-config-services), to turn on the spamassassinservice. Refer to Section 4.2, “Runlevel Utilities” for more information about initscript utilities.To configure Procmail to use the SpamAssassin client application instead of the Perl script,place the following line near the top of the ~/.procmailrc file. For a system-wide configuration,place it in /etc/procmailrc:INCLUDERC=/etc/mail/spamassassin/spamassassin-spamc.rc5. Mail User AgentsThere are scores of mail programs available under Red Hat Enterprise Linux. There areMail User Agents207
