Authentication is a plugin designed with private servers in mind. It makes it possible to setup one without having to worry about Steam Groups nor SteamIDs. Just choose a password of your preference and you're ready to go.
After wake up, players will be requested to enter the /auth command along with the password the server owner should have shared with them.
There's a limited time to enter the command after the wake up, if players fail to authenticate before the time runs they're...