My guess would be that the far end has taken one look at what you sent and dropped the connection so fast that feet are not in contact with the ground.

I suppose it's possible that the conversation did not go quickly enough for the far end, and it has timed you out and closed the connecton with similar effect feet-and-ground-wise.

You could try telnet and see if you get the same effect. Though there I guess the problem will be computing the responses to the challenges and typing them in quickly enough !