Today I had trouble connecting to XS4all. I tried it once and the screen stopped at "connected", no map loading commenced. I closed ezQuake, restarted it and tried connecting again - this time it worked.

Just now I tried connecting again, and just like before the client stopped at the "connected" message. I restarted ezQuake, tried connecting and received a message that I was BANNED. I don't understand it, is there some script which bans users for frequent reconnecting? I don't recall doing anything ban worthy. My in-game nick is "Patrol". Can anyone please explain the situation?

Are you using a proxy ?

ezQuake says "connecting using 1 proxy" so I guess I am. I haven't changed nQuake's default settings in this regard.

On a positive note, my ban has been lifted, but still I would appreciate info on what causes such temporary bans, for future reference.

Well proxy are banned by xs4all, so maybe you had a routing problem and ezquake used one to get you a better ping...

Sounds reasonable. May I ask why XS4all does not allow any proxies? Are they a bad thing?