> Perhaps it was the timing? Were the successful and unsuccessful
> connections made at different times? It's entirely possible that SSH
> connections from outside are accepted during the working day and
> rejected out of hours. If you try getting a connection at various times
> of day this could be tested.
I think it's likely that he gets denied a connection when he is home
(outside working hours) and then allowed SSH connections when the sysadmins
are in duty. This prevents the possible accumulation of zombies, at least
assuming that you have entire clusters with high bandwidth backbones. It is
worth finding out if there are restrictions based on hours. The OP knows
better when he attempted to connect remotely, so can make better judgement.
Roy S. Schestowitz