It looks like ssh is looking at /etc/host.conf AFTER reading /etc/resolv.conf and trying to do a DNS lookup. This is not good, because then it doesn't respect the host.conf ordering on name resolution. A Debian ticket has been opened, and is listed in the URL. You will find an strace of the problem there. (I'm not sure if sshd has this problem, when it comes to reverse DNS checking. Can we confirm this as well?)
what's host.conf? ssh does not even look at resolv.conf
Further investigation reveals that this is not an SSH bug.
Mass change of RESOLVED bugs to CLOSED