MutReservedSlot
MutReservedSlot is a reserved slot system coded in UnrealScript for Unreal Tournament 2004. It uses LibHTTP 3.5 to connect to a page of your choice, and looks for a specific return code to determine the user's access level.
The script hasn't been maintained in a long time and it's uncertain if it works with LibHTTP 4.0. Perhaps it'll be updated some day.