/SLASHPLAY
How to see the ban list in GMod
Type listid in the server console to list every banned SteamID currently loaded, both timed and permanent.
listid
Lists the SteamIDs currently on the ban list.
listid Examples
listid Show banned SteamIDs.
What it does
Shows both timed and permanent bans currently loaded.
The game's own description: Lists banned users.
Run it on your server
On a SLASHPLAY server, type it in the Console tab of the server page; the reply shows right under it. A value set there lasts until the server restarts. To keep it, add the line to garrysmod/cfg/server.cfg. New to this? Start a GMod server first.
Your own
GMod server.
From $0.03 an hour, only while it runs. New accounts get 6 free tokens.