[Samba] Can Logon & Join NT4-style Domain, Can't Change Password

[Bill Baird]

Hi All,

Our users started having issues late last week when trying to change their
passwords. They receive the following message:

"The system detected a possible attempt to compromise security. Please
ensure that you can contact the server that authenticated you."

Client computers are running Windows 7 Ultimate & Enterprise x64. We are
still running (I know, I know) and NT4-style PDC domain (DC is running
Samba 3.6.24-45).

Users are able to use network drives normally. We can add computers to our
domain successfully.

>From some searching, this appears to sometimes happen when a domain running
AD also has an NT4-style server available and the system is trying to use
the NT4-style server instead of AD? I'm just not sure how this could be
possible, since we don't have any servers that are configured this way
(only two people have access, and definitely didn't modify things).

I am also seeing some results saying it might be a DNS issue. I have done
some testing and as far as I can tell, my DNS & WINS is operating as
expected.

Has anyone seen this before? Or have any ideas on what I can do to
troubleshoot?

Thanks!

--Bill