Hey,
You are probably referring to the id software master server, but we are running one on our own.
In order to host a game (without hamachi), start a dedicated server. If your server is behind a NAT (firewall/router/whatever you call it), make sure to forward port 27960 (or whatever port you configure when starting the server) to the ip of the computer that runs the server.
After a while the server should show up in the internet server list, or you can check it in your browser: http://master.rtcwcoop.com/
to join a dedicated master server that runs on your computer you might need to use the console to connect to it. Open the console (press shift-esc) and type: /connect 0.0.0.0
if that doesn't work, try /connect 127.0.0.1 or /connect <local ip of your computer>
about the resolution: The menu files aren't up to date for the latest resolutions, we haven't touched the source code of this mod in ages.
