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.
Some setting in Tweak 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