shares \\domain\netlogon and sysvol inaccessible

[m.guarnieri at sicim.org]

Dear all,
We start using Samba 4 from the alpha 14 (I think we start on June/July
2011) on the production environment. I've never had big issue, and anyway
reading the mailing-list or searching google I've always find a solution.
But not this time...
We have 6 domain controller on 5 different location (connected by
Site-to-Site OpenVPN). The last DC have been added on April 2013. On May
29 I notice that the policy folder and netlogon folder have become
inaccessible. If I try to access to \\domain.loc\sysvol (or netlogon) I
get:

"\\domain.loc\sysvol is not accessible. You might not have permission to
use this network resource. Contect the administrator of this server to
find out if you have access permission.

An internal error occurred."

I've notice this error only on Windows 7 (we don't have Vista or Windows 8
client), Windows XP SP3 works correctly!
if I try to access the servers directly (all of them) it works. If I try
to access the same share (\\domain.loc\sysvol) from a Windows XP client,
it works. If I try to access to the share (\\domain.loc\sysvol) from any
of the other five remote location it works! NSLOOKUP shows the servers
correctly...

C:\>nslookup domain.loc
Server:  server1.domain.loc
Address:  192.168.1.95

Name:    domain.loc
Addresses:  192.168.1.95
          192.168.1.251
          192.168.3.95
          192.168.10.95
          192.168.0.95
          192.168.2.95


I read this kind of problems are usually related to a misconfigured DNS,
what should I check? To me seems good...


Thanks for your support!
Marco