As a system administrator you might often use CSF to block / unblock your server visitors. There are a lot of tutorials how to do that via GUI. Anyhow in this article I will share an easy way to administrate your firewall using command line.

Here are the most useful command flags I use all the time:

Restart CSF:

csf -r

Deny an ip address:

csf -d xxx.xxx.xxx.xxx 

Quick allow / whitelist an ip address:

csf -a xxx.xxx.xxx.xxx

Unblock an ip address and remove from the deny list:

csf -dr xxx.xxx.xxx.xxx

I hope you will find this information useful.