Tweaks to prevent Spamming on cPanel server.
Setting in – Exim Configuration Manager
1. Login to WHM control panel by using root user
2. Goto Main >> Service Configuration >> Exim Configuration Manager
3. Enable RBL filtering by Basic Editor >> RBLs >> switch to – On and if you like you may additional RBL from manage option.
4. Sender Verification Callouts = ON
5. Sender Verification = ON
5. Reject SPF failures =ON
6. Then save all the configuration this will stop most of spams in the server.
Then go on tweak setting to modify some setting:
1. Login to WHM control panel by using root user
2. Goto Main >> Server Configuration >> Tweak Settings
3. Initial default/catch-all forwarder destination = Fail
4. Max hourly emails per domain = 200
5. Count mailman deliveries towards a domain