do you have one of the 2wire routers? They do support dmz. It's on the Firewall Settings page.
You can get to the app for your network setup by going to the System-->Administration-->Network or by running system-config-network from a terminal.
If you need to give them unlimited access, you will still need to allow the access in iptables even after setting it up as dmz in your router.
also, if you need the mac address, you can get it from the router as well
if you have the 2wire router here is the link for the page that gives you the device list: