APF Advance Policy firewall that provides you an easy way to configure iptables rules. This is a short snippet how can you install/configure or uninstall APF on your Linux Server.
wget http://www.rfxn.com/downloads/apf-current.tar.gz
tar -zxvf apf-current.tar.gz
cd apf-9.7-2
./install.sh
APF installation is completed.
How to allow specific incoming ports in APF ? e.g 80,21
vim /etc/apf/conf.apf