Host Access Control is a feature in WHM that allows you to set up some rules to allow or deny access to your server. It is an overall better choice allowing connections that you wish to proceed is the most secure way to use Host Access Control rather than denying all connections.
You can use Host Access Control feature to allow or deny clients’ access, based on the IP address, to the following services:
Daemon Name Service Name
pop3 POP3 (Courier or Dovecot)
imap IMAP service (Courier or Dovecot)
To allow or deny services in Host access control panel please follow the below steps.
1) Login to WHM.
2) Click on “Host Access Control” under “Security Center” section.
3) From the next screen, you can input the rules. These rules have three parts. In the first part, you need to specify which service that you want to set and the next field is “Access list”, that means the IP address that you want to set the rule and then “Action” field which allows you to grant the action.
4) After entering the rules, you need to save it. You need to click “Save Host Access List” button to save the changes.