How to enable Spam protection on a cPanel server
This guide will walk you through installing and configuring common anti-spam tools on your VPS/Dedicated Server.
SpamAssassin and ClamAV are open source tools to help stop incoming spam on your Virtual or Dedicated cPanel server. SpamAssassin is an open source Spam filter for detecting and filtering spam email message, and ClamAV is an open source anti virus scanner. Both are easily installed through WHM on your Dedicated or Virtual server.
Install and Enable SpamAssassin
Go to Server Configuration -> Tweak Settings. Find the mail section, and click on "Enable SpamAssassin spam filter". Scroll to the bottom and click the Save button.
Install and Enable ClamAV
Go to cPanel -> Manage Plugins. Click the "Install and Keep Updated" check box under clamavconnector. Click the Save button.
Configure Exim Settings
Go to Service Configuration -> Exim Configuration Manager. Check that the following options are enabled:
ACL Options
Reject remote mail sent to the server's hostname. "SpamAssassin ratelimit spam score threshold" should be set to 20.
Filters
"SpamAssassin Bounce Mail when the spam score is greater than" should be set to 15.
Log sender rates in exim.
Security (requires ClamAV)
Scan messages for Malwate from Authenticated Senders.
SpamAssassin Options
SpamAssassin: Forced Global ON.
Configure a Reputation Block List
You will also want to configure an RBL to help filter out mail from the most prolific spammers.