Homepage: http://www.configserver.com/cp/csf.html
Description: Advanced Policy Firewall (APF) is an iptables(netfilter) based firewall system designed around the essential needs of todays Internet deployed servers and the unique needs of custom deployed Linux installations. The configuration of APF is designed to be very informative and present the user with an easy to follow process, from top to bottom of the configuration file. The management of APF on a day-to-day basis is conducted from the command line with the apf command, which includes detailed usage information and all the features one would expect from a current and forward thinking firewall solution.
Pre Setup: Make sure perl modules are installed
yum install -y perl-libwww-perl
Step 1: Download, unpack, install of APF from source.
cd /usr/local/src wget http://www.configserver.com/free/csf.tgz tar -zxvf csf.tgz cd csf ./install.sh
Step 1.1: Cleanup source install files.
rm -Rf /usr/local/src/csf* && cd
Step 2: Backup orginal CSF config
cp /etc/csf/csf.conf /etc/csf/csf.conf.bak
Step 3: Edit current CSF config
nano -w /etc/csf/csf.conf