Fake rcon adds the fake_rcon_password and fake_rcon command because valve has not integrated the original command into the game (or it is broken).
https://forums.alliedmods.net/showpost.php?p=2811082&postcount=15
The password must be at least 4 characters long. We use a file because convar management is not yet complete on the cs2 SDK
fake_rcon_password YOURPWD
fake_rcon say hello