/SLASHPLAY
How to unban a player on a TF2 server
Type removeid [U:1:12345678] in the server console to lift that Steam ID ban, then run writeid to save the change.
removeid
Removes a Steam ID or user ID from the ban list.
removeid <steamid> Examples
removeid [U:1:12345678] Unban a Steam ID.
Arguments
steamidRequired- Steam ID to unban.
What it does
Run writeid afterwards so the unban is saved.
The game's own description: Remove a user ID 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 tf/cfg/server.cfg. New to this? Start a TF2 server first.
Your own
TF2 server.
From $0.03 an hour, only while it runs. New accounts get 6 free tokens.