Для начала закачать сервер:
(update.bat)
hldsupdatetool.exe -command update -game left4dead -dir D:\L4D

Запустить:
(start.bat)
srcds.exe -console -game left4dead +maxplayers 8 +map l4d_vs_b_4 +sv_lan 0 +exec server.cfg

Пример server.cfg
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//Host Name
hostname Server "******"
// Rcon Cvars
rcon_password "********" //Set's remote control password

//Search Key
sv_search_key "********"

// Server password
sv_password ""

//in game browser
sv_flags "Browser"

// Server Cvars
mp_disable_autokick 1 //Prevents a userid from being auto-kicked
sv_allow_color_correction 0 //Allow or disallow clients to use color correction on this server.
sv_allow_wait_command 0 //Allow or disallow the wait command on clients connected to this server.
sv_alltalk 1 //Players can hear all other players, no team restrictions
sv_alternateticks 0 //If set, server only simulates entities on even numbered ticks.
sv_cheats 0 //Allow cheats on server
sv_clearhinthistory 0 //Clear memory of server side hints displayed to the player.
sv_consistency 1 //Whether the server enforces file consistency for critical files
sv_contact "your_admin@whatever.com" //Contact email for server sysop
sv_downloadurl "" //Location from which clients can download missing files

// Lan or internet play, Server region cvars
//sv_lan 0 //Server is a lan server ( no heartbeat, no authentication, no non-class C addresses )
sv_region 0 // Region Codes: 0 - US East coast, 1 - US West coast, 2 - South America, 3 - Europe, 4 - Asia, 5 - Australia, 6 - Middle East, 7 - Africa, 255 - world

// Server Logging
sv_log_onefile 0 //Log server information to only one file.
sv_logbans 1 //Log server bans in the server logs.
sv_logecho 0 //Echo log information to the console.
sv_logfile 1 //Log server information in the log file.
sv_logflush 0 //Flush the log file to disk on each write (slow).
sv_logsdir "logs" //Folder in the game directory where server logs will be stored.

//Server Rates
sv_steamgroup_exclusive 1 // <1> Do not connect to the Match Making Service
sv_allow_lobby_connect_only 0 // Allow connections without creating lobby
sv_visiblemaxplayers 8 // Visible Player Slots
sv_maxcmdrate 100 //(If sv_mincmdrate is > 0), this sets the maximum value for cl_cmdrate.
sv_unlag 1
sv_maxunlag .5

//Fix to get your server onto the master lists
setmaster add 68.142.72.250:27011
setmaster add 72.165.61.189:27011
sv_steamgroup //this is your group's steam group id.. allows members to join from main menu add

//sv_steamgroup_exclusive 1 //to make it exclusive and private
// Difficulty of the current game  (easy, normal, hard, impossible)
z_difficulty normal
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