SpamAssassin is implemented as the /usr/bin/spamassasin script, which is a Perl script. There is some performance overhead involved in running a Perl script for each email. For sites with low volumes of email, this may not be an issue, but performance is a high priority for high volume sites. In these cases, the SpamAssassin daemon can be used to improve performance.
When SpamAssassin is used as a daemon, /usr/bin/spamd is run at system startup, and /usr/bin/spamc is used as a client. When used in Procmail recipes, /usr/bin/spamc and /usr/bin/spamassassin are often interchangeable, although they support different flags.
The spamc and spamd programs are installed with SpamAssassin. The SpamAssassin distribution directory includes sample initialization scripts for starting the daemon. They are located in the spamd directory of the SpamAssassin build directory.
The spamd daemon supports...
