Hehe, so here's the thing... I installed Anubis to protect this forum from bots. And what Anubis does is check the ip address of the user. If it's OK, it lets you pass, otherwise you won't get in. So far so good. But.. what Anubis does is forward you to the forum with a universal ip address. And that ip-address was flagged as suspicious by phpbb. So everybody got banned all of the sudden. I've configured Anubis that this won't happen again.
We learn something every day :-/