IPCop is a dedicated Linux firewall that can be installed on modest PC hardware. It is almost certainly a waste of resources to install it on the most modern PC hardware, although you can, far better is that PC that you have just replaced or even one that has been sat around gathering dust. An alternative and the way I run mine, now, is to have it running in a virtualbox VM. This is hosted by an PC running an ubuntu server and also running as a VM is a DMZ server.
The homepage says "IPCop Linux is a complete Linux Distribution whose sole purpose is to protect the networks it is installed on. By implementing existing technology, outstanding new technology and secure programming practices IPCop is the Linux Distribution for those wanting to keep their computers/networks safe". This is a job it does very well, although purists may not aprove of my current ipcop in a VM set-up. However utilising iptables in the host ubuntu server I have blocked all access from red/orange that isn't directed to ipcop.
I used IPCop from version 1.3 through to 2.0.2, having previously tried it's predecessor smoothwall. I prefer IPCop. It looks better, has great support on the mailing list and is easily configurable. Version 2 has significantly improved the functionality of version 1.
Here you'll find links to all the adjustments that I have carried out to my ipcop to make it what I want it to be. These adjustments apply to ipcop version 2 (you'll see the exact version of 2, in the appropriate pages (top right)). My older 1.4.21 modifications are still on this site, if you want to refer to them. They were tested on 1.4.21 but should work on the earlier 1.4 series products with minor adjustments, but if you take your protection seriously you really ought to be on a late version of IPCop anyway.
This site is not part of, nor endorsed by, the official ipcop website or developers. I offer it to you in the hope that it will add value to the standard ipcop install.
Comments and requests for assistance may be made via the contact me page.
Allan Kissack (a snapshot of my latest graphs is here.)