[chromaton]

I've successfully used an HTTP tarpit to cut down on registration spam. The attacks were being launched from only a handful of (presumably compromised) hosts. If I blocked them, they'd switch to a different attacking host. But I discovered if I tarpitted them, they'd be slowed down to the point where they weren't a problem any more.

[jchook]

How did it work?

[chromaton]

Something like:

  if(IP==attackerIP) {
    for 10000 times
       write random byte
       sleep 10 seconds
  }