Utilizing SUSE Linux Enterprise Server as a Network Firewall / Proxy Server
This article shows you how to utilize SUSE Linux Enterprise Server as a fully functioning network Firewall, including the ability to utilize a “Transparent Proxy Server” and to filter the Internet Access with SquidGuard. Also covered is the implementation of monitoring software to show you where your users go on the Internet and how much Internet bandwidth your network uses.
Read this article at: http://www.pcc-services.com/sles/firewall.html
Disclaimer: As with everything else in the SUSE Blog, this content is definitely not supported by SUSE (so don't even think of calling Support if you try something and it blows up). It was contributed by a community member and is published "as is." It seems to have worked for at least one person, and might work for you. But please be sure to test, test, test before you do anything drastic with it.