Let’s say that you want to check whether or not a specific IP address, maybe 8.8.8.8 , is blocked by CSF. That’s easy!
csf -g 8.8.8.8
Unblock an IP Address
If the IP address is denied in CSF and you want to remove it, then use this command:
csf -dr 8.8.8.8
CSF then needs to be restarted for the change to take effect:
csf -r
https://www.liquidweb.com/kb/how-to-unblock-an-ip-address-in-csf/