Checkpoint64 has a preset for Left 4 Dead 2 (Dedicated Server): it already knows where the config folder is, backs it up automatically and keeps every version. Everything this site has on Left 4 Dead 2 (Dedicated Server):
Left 4 Dead 2 (Dedicated Server)
-
Config file location
Windows:
C:\Program Files (x86)\Steam\steamapps\common\Left 4 Dead 2 Dedicated Server\left4dead2\cfg -
Backup guide
Competitive games keep your progress on their servers — what's on your disk is the config. Checkpoint64 versions the settings folder for 67 games and 16 dedicated servers, so a reinstall or a file verification can't cost you your binds. Free download.