Basic setup question

I have an xserve running behind a router with all ports forwarded to it. I am currently working on getting a fully qualified domain name setup with our ip addy. my question is should i keep my current setup the way it is or should i make the server become the router and host everything on our network. i want to make all security protocols work and they require a Fully Qualified Domain NAme and I'm guessing keeping it behind the router is apart of my problem. i'm sure i will run into a slew of new problems but i wanted to check with someone regarding the initial steps.