How to enable Spam protection on a cPanel server
How to filter spam and virus emails
Install and Enable SpamAssassin
SpamAssassin is an open source Spam filter for detecting and filtering spam email message.
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
ClamAV is an open source anti virus scanner.
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 (RBL)
You will also want to configure an RBL to help filter out mail from the most prolific spammers.