tor 0.2.1.24 guesses random exit IPs when node hostname doesn't resolve

[This may or may not be related to task legacy/trac#827 (moved).] [I have not tested this on anything buy Mac OS X 10.5.8; it may or may not occur on other OSes.]

host.department.example.edu has IP address XXX.YYY.ZZZ.WWW when looked at from inside example.edu.

host.department.example.edu has no IP address (NXDOMAIN) when looked at from outside example.edu. XXX.YYY.ZZZ.WWW is outside example.edu, so it cannot look up its own address from its name.

This failure of DNS resolution causes a service outage in the face of tor 0.2.1.24's IP address guessing, which fails badly, to the point of picking apparently randomly distributed IP addresses.

This failure of DNS resolution does not cause a service outage in tor 0.2.1.22, though the situation is logged.

I will attach or provide links to debug log files.

[Automatically added by flyspray2trac: Operating System: OSX 10.5 Leopard]