RedHat 9 is kinda old…. If you are looking for a “free” OS in place of W2K3, look at Fedora Core. It is the new RedHat “free” version.
You can use it for anything that Winders will do – File server, firewall, proxy, email, database, etc. And, unlike Winders, it’s all in there. Download all of the ISOs and have a blast!