ConfigServer Security & Firewall (CSF) allows you to manage your iptables configuration. CSF is a simplified interface that makes it easy to add or remove IP addresses from your firewall.
NOTE: You must either have root or reseller access to configure the firewall. cPanel users can NOT access firewall functions.
Once you have logged in this will return you to the main page of your WHM on the left hand side menu left click ‘ConfigServer Security&Firewall’ This will open the web interface for configuring (CSF)
First of all we have to check to see why the IP was listed in the first place. In the ‘Search for IP’ enter the IP that is suspected to being blocked then left click ‘Search for IP’
ConfigServer Security & Firewall (CSF) will then query it's records and show you what it has for that IP.
For example, here is what a blocked IP address looks like when searched for:
You can click the padlock icon to unblock the IP.
Most of the options are explained, but to configure a firewall, there are three options that are most important : Quick Allow, Quick Deny, and Quick Ignore. Simply enter the IP address into the coloured box, and left click the ‘Quick Allow’, ‘Quick Deny’ or ‘Quick Ignore’.
If you want to whitelist a IP address to the server, you can add the IP to "Quick Allow". Once applied, you then will want to add the IP to "Quick Ignore".