[Samba] password authentication failing for winbind

[Gawain Lavers]

I originally posted this issue with the heading "winbind: challenge/response
password authentication failed".  I was using the redhat 7.3 samba 2.2.3 rpm
then.  I've upgraded to 2.2.5, but all that's changed is the return message.

wbinfo -a VENUS0+tassadar%torque

used to get me:

 plaintext password authentication succeeded
 challenge/response password authentication failed
 Could not authenticate user VENUS0+tassadar%torque with challenge/response

now it gets me:

 plaintext password authentication succeeded
 error code was NT_STATUS_OK (0x0)

A couple of points of interest:  I can su to VENUS0+tassadar when I start as
root (I suppose because root doesn't have to provide a password to take on an
identity), but if I try to su to that account from another user account, I'm
challenged for a password, and get the response "su: incorrect password", but
even this is interesting, because if I enter the _wrong_ password, I get a
second password prompt, while if I enter the correct one, I get the error
message immediately.

I ran "/usr/sbin/winbind -i -d 100", but nothing is output when I use wbinfo,
try logins, etc.

Does anyone have any debugging suggestions for me?  This must be something
really basic, since I'm hardly trying to do anything fancy here, and I'm using a
pretty stock installation/conf files.