How to install the csf firewall on Linux Server
CSF firewall commonly known as Configserver Security and Firewall has become one of the popular firewall not just because of its easy of use it also provides a cpanel interface and can be easily installed and tuned by any novice users. If you are running cpanel without firewall then CSF firewall is very much recommended, considering the security aspects of your server.
cd /usr/src
wget http://www.configserver.com/free/csf.tgz
tar -xzf csf.tgz
cd csf
sh install.sh