/SLASHPLAY
How to unban an IP address in GMod
Type removeip 203.0.113.5 in the server console to lift that IP ban, then writeip to save the change.
removeip
Removes an IP address from the ban list.
removeip <ip> Examples
removeip 203.0.113.5 Lift an IP ban.
Arguments
ipRequired- IP address to unban.
What it does
Run writeip afterwards to save the change.
The game's own description: Remove an IP address from the ban list.
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.