This guide will help you how to whitelist an IP address within CSF or ConfigServer Security & Firewall. Before whitelist an IP address, you need to understand how to get your own IP address. In this case, you can use myip.dk.
Go to WHM portal and login as root.
Search for CSF plugin menu from WHM search panel.
Scroll down a bit and find csf Quick Actions.
Now input your own IP addres within green row provided above. And then click Quick Allow.
Congratulations! Your own IP address has been whitelisted!