In part two of this series we're going to discuss adding firewall rules to the router.  Everyone knows that adding ingress (or incoming) firewall rules is important to securing your network.  However, the same can be said for adding egress rules for traffic leaving your network.  For instance, aside from an email server, no client should ever send traffic to the Internet via TCP port 25.  If you see traffic like this, it could mean that you have an infected computer within your network.

This will be part 1 in a series of configuring CentOS/Red Hat 6 as a secured firewall. Though I am a huge fan of pfSense (which can be found here pfSense), I wanted to build my own from scratch. So, the first part of this series will consist of setting up PAT (or NAT overload for the Cisco geeks) on Linux.

The first step is to configure the network cards.  In this scenario we will use eth0 as the WAN connection and eth1 as the LAN connection.  Refer to the diagram below

In order to get the AE2500 wireless USB adapter to work you must install ndiswrapper. First, the ndiswrapper-1.57 version is not compatible with the 3.3 or 3.4 version of the Linux kernel so you must install the ndiswrapper-1.58rc1 which is still in test as of this writing. Next, download the AE2500 Windows XP drivers from the Linksys website ( Link ).

Mounting a USB device