(for me I need to put in my tunngle ip(its the number the hovers over your name when your in tunngle) as well as a default 27016 in the port in the Teknogods launcher when I start a server to be able to connect to it. You might need to forward the ports to do this, also tunngle uses port 11155 by default)
Call of Duty Modern Warfare 3 Dedicated Server Tutorial for use over LAN using the software called Tunngle.
***tutorial links and other info***
Here are the files you need to set up your game folder.
Where do the files go?
The (update 1.4 patch) package, you can use those for main, zone, and you also need to drag the player2 folder from there as well as you see in the video. You also need to make sure the admin folder from the (update1.4+server files file pack) is placed in your game folder.
Here is the command to put in server counsel to start the server, you will have to change out the parts that say name.
sv_maprotation name;start_map_rotate;sv_hostname name
If you want to edit how long each map is played that is done through your player2 folder, changing the dsr file your using for that map. You simply open file with notepad, then use the find option in the edit menu, then search for time, once you find that you can change that to how ever long youw want that game mode to play your maps. Just save it and your next map with that gamemode will use the new time.