Left 4 Dead LAN Config
Well, guys…. You don’t have to patch to play LAN in Left 4 Dead. Here are the steps to play LAN. Good for home LAN parties. Haha!! :)
At the game menu click > Options > Keyboard/Mouse > Enable the Developer Console
In the console, type
1. sv_lan 1
2. sv_allow_lobby_connect_only 0
4. Choose your map. Type map and hit space. You will be able to see a list of maps bellow. Maps with VS are versus maps.