[Samba] Windows machines (WINXP, WIN2K) can/will not join domain

[Chartier, Prescott W CIV NUWC NWPT]

We have been running  Samba v3.0.32 On Red Hat Linux for probably 2
years now (or since it was released).  Recently over a three week
period, all the Windows clients slowly dropped from the domain one by
one and we are unable to get them to re-join the domain.  We are still
able to map to drives and printers on the Samba server and use them with
no problem, but cannot join the domain.  We need to be able authenticate
users on the domain and cannot.  There have been no changes to the
system or the network involved, which is a standalone network with no
access to the internet.  Yet obviously SOMETHING has changed, we just
cannot figure it out.  When we attempt to join the domain, we get the
error below:


************************** Begin error message
******************************
NOTE: This information is intended for a network administrator.  If you
are not your network's administrator, notify the administrator that you
received this information, which has been recorded in the file
C:\Windows\debug\dcdiag.txt.

The domain name simpledomain might be a NetBIOS domain name.  If this is
the case, verify that the domain name is properly registered with WINS.

If you are certain that the name is not a NetBIOS domain name, the
following information can help you troubleshoot your DNS configuration.

The following error occurred when DNS was queried for the service
location (SRV) resource record used to locate a domain controller for
domain simpledomain:

The error was: "This operation returned because the timeout period
expired."
(error code 0x000005B4 ERROR_TIMEOUT)

The query was for the SRV record for _ldap._tcp.dc._msdcs:simpledomain

The DNS servers used by this computer for name resolution are not
responding.  This computer is configured to use DNS servers with the
following IP addresses:

xxx.xxx.xxx.xxx
xxx.xxx.xxx.xxx

Verify that this computer is connected to the network, that these are
the correct DNS server IP addresses, and that at least one of the DNS
servers is running.

**************************  End error message
******************************

Please understand that we have checked and recheck the DNS and both are
responding as one would expect.  We are able to resolve the simpledomain
to its correct IP address on all the affected machines, so that isn't
the problem.  We do not use ldap, this is just a simple implementation
of Samba.  Anyone with any ideas??

Thanks for any assistance you may provide.

Prescott ...