ConfigServer Firewall (or CSF) is a free and advanced firewall for most Linux distributions. In addition to the basic functionality of a firewall – filtering packets – CSF includes other security features, such as login/intrusion/flood detections. CSF includes UI integration for cPanel, DirectAdmin and Webmin.
In order to install CSF , login to your server with root user
Download the CSF installation pack
The downloaded file is a compressed form of a tar package, and has to be uncompressed and extracted before it can be used. To extract the file use the command and hit enter.
tar -xzf csf.tgz
Now it is time to execute the CSF’s installer script. Move to the csf directory and execute the installation script as shown below.
The firewall is now installed, but you should check if the required iptables modules are available. You can check it with below command
perl /usr/local/csf/bin/csftest.pl
The firewall will work if no fatal errors are reported