Shark,

There were DoS attacks a few years back that involved conditions like the ones you have provided. Many have since been patched but yes, you used to be able to get a box to enter into an endless loop and deny services to legit users. I have to say that it wouldn't surprise me to see more attacks like this again. I was certain that with raw socket support in XP that we'd see many more issues but surprisingly, the avalanche has not happened - yet