Left 4 Dead: Hint (How to Run Over LAN)

Comp server:
1) In the game, in the settings, activate the console
2) in the console, enter the following commands (commands are entered sequentially without commas): sv_cheats 1, sv_lan 1, map * (where * is the level map)

Comp client:
1) In the game, in the settings, activate the console
2) enter the following commands in the console: sv_cheats 1, sv_lan 1, connect x (where x is the IP of the computer server)

100% works on our client.