Spam Filter

SpamAssassin is free and open source software used for e-mail spam filtering based on content-matching rules. It is now part of the Apache Foundation.

SpamAssassin uses a variety of spam-detection techniques, that includes DNS- based and fuzzy-checksum-based spam detection, Bayesian filtering, external programs, blacklists and online databases.

The program can be integrated with the mail server to automatically filter all mail for a site.

Software Installation

SpamAssassin is in the Ubuntu software package repository:

$ sudo apt-get --install-suggests install spamassassin

Configuration

The SpamAssassin system service and the cron-job for daily rule updates rules update aren not enabled by default.

Open /etc/default/spamassassin and change as follows:

# Change to one to enable spamd
ENABLED=1

# Cronjob
# Set to anything but 0 to enable the cron job to automatically update
# spamassassin's rules on a nightly basis
CRON=1

Service Start

Now start Spamassassin:

$ sudo /etc/init.d/spamassassin start