I've got some sort of reverse DNS problem with OS X, but I'm not quite sure why. Basically, ssh takes forever to initialise the connection and a verbose trace shows that it's timing out trying to map the IP address of the target box to a hostname. I've checked all the obvious area:
/etc/hosts is correct, NetInfo is shiny, lookupd has been tweaked to consult files and NI ahead of DNS, but the problem remains. Hmm...