CSF (ConfigServer Security & Firewall) is considered an advanced firewall given it has many more configuration options than most other software firewalls, such as APF. Additionally, is simple enough to install and configure on Linux servers, even for novice system administrators.
1. Look for your IP Address in CSF
If you want to check whether or not a specific IP address, such as 192.168.2.1, is blocked by CSF, you need to issue the following command:
csf -g 192.168.2.1
2. Unblock an IP Address
If the IP address is denied in CSF and you want to remove it, then use this command:
csf -dr 192.168.2.1
3. CSF needs to be restarted for the changes to take effect:
csf -r
or
