[Samba] DNS Problem with 2 Domain Controllers

[Zane Zakraisek]

Hi!
We've got two domain controllers (DC1, DC2) running 4.5.0.
We had to perform maintenance on DC1, so we took it offline, thinking
nothing of it.
The clients (Debian 7 running winbindd, some 4.4, others 4.5), were not
able to resolve names or groups anymore...

Starting winbindd in debug mode on one of the clients, I could see that it
was indeed talking to DC2, but was not able to perform user/group lookups.

The resolv.conf files on all the machines have DC1 first, then DC2.
I simply removed DC1 from resolv.conf, restarted winbindd, and everything
worked great.
I then put DC1 back at the top of resolv.conf, and users/groups did not
resolve anymore.

Is this a bug in winbindd on the client side, a bug on the server side, or
simply a bug in the local DNS resolvers?

ZZ