I have been looking different firewalls for Linux Centos 5.5 and have decided that firehol will be the easiest way to implement iptables.
However I need help configuring it. This is my senario...
I have a (physical) server sitting in a datacenter, it has one Ethernet network connection (to the internet). The server will be running VoIP for around 20 businesses so I want to restrict access to the server based on IP addresses as well as ports, as all the customers will have static IP Addresses.
So only authorized customers will be able to access the server and then only to authorized ports.
How would I accomplish this using iptables and firehol?