How to Start a LAN Campaign on 'Left 4 Dead'

1. Insert an Ethernet cable into the Ethernet port on each computer. Connect the other end of the Ethernet cable to the Ethernet ports on the LAN switch.
2. Click the 'Start' button on whichever computer you wish to be the host computer. Click the 'Start Search' option. Type 'cmd' in the space provided and press the 'Enter' key. In the Command Line Interface screen that pops up, type 'ipconfig.' The CLI will now display your LAN IP address. Write the IP address down.
3. Run 'Left 4 Dead' on each of the computers being used. On the host computer, click the 'Options' tab, select the 'Keyboard/Mouse' option and click the 'Developer Console' option to enable it.
4. Type 'sv_lan 1' in the space provided and press the 'Enter' key. Type 'sv_allow_lobby_connect_only 0' and 'net_start' each followed by the 'Enter' key.
5. Type 'map' in the developer console to bring up the list of maps. Press 'Up' and 'Down' on the keyboard's arrow keys to highlight the map you want to play. Press the 'Enter' key.
6. Bring up the developer console on each of the client computers. Type 'connect xxx.xxx.xxx.xxx' in the console, replacing 'xxx.xxx.xxx.xxx' with the LAN IP address you wrote down in Step 2. Press the 'Enter' key to connect to the host game.