Exim Configuration Manager
1. Login to WHM control panel
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 {Personally I disabled this option as it was introduced as a feature in the mail server to arrest inbound spamming – Inbound spam can be tolerated to some extent}.
5. Sender Verification = ON
5. Reject SPF failures =ON
6. Then save all the configuration settings.
Configurations 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
Also, select the system to hold or reject a potential spammer.
After This Also Enable Greylisting
Enable Imunify Email
ImunifyEmail is an Imunify360 add-on that offers advanced email protection, prevents unauthorized bulk mailings, reduces spam-related support tickets, and ensures email delivery.
Check it is enabled or not with the following command.
[root@srv ~]# ie-config enable
[root@srv ~]# ie-config status
spamfilter exim configuration: enabled
rspamd state: active (running)
ie-quarantine state: active (running)
ie-dec-node state: active (running)