Set Up SpamAssassin on CentOS/RHEL to Block Email Spam

Previously we discussed 7 effective methods for blocking email spam with Postfix SMTP server. In this tutorial, we are going to learn how to use SpamAssassin (SA) to detect spam on CentOS/RHEL mail server. SpamAssassin is a free, open-source, flexible and powerful spam-fighting tool.

SpamAssassin is a score-based system. It will check email message against a large set of rules. Each rule adds or removes points in the message’s score. If the score is high enough (by default 5.0), the message is considered spam.

Install SpamAssassin on CentOS/RHEL

Run the following command to install SpamAssassin from the default CentOS/RHEL software repository. Spamc is the client for SpamAssassin spam filtering daemon.

sudo dnf install spamassassin

The binary installed by the spamassassin package is called spamd, which will be listening on TCP port 783 on local host. By default, the spamassassin systemd service is disabled, you can enable auto start at boot time with:

sudo systemctl enable spamassassin

Then start SpamAssassin.

sudo systemctl start spamassassin

Read full tutorial here: https://www.linuxbabe.com/redhat/spamassassin-centos-rhel-block-email-spam