Check out Vyatta.. they have an appliance or it can be run on a computer/VM. They have a commercial version and a community version.

I still play when I get the time. Great for casual players and hardcore raiders alike. The community is helpful and there have been many steps to root out the cheaters and keep it fun for everyone.

and single servers, http://www.shardsofdalaya.com/ for those of you who would enjoy a new twist on an old game.. MMO, singe server, great community, and fun.