[Samba] Dynamic DNS updates not working with BIND DLZ

[Thomas Simmons]

On Wed, Apr 10, 2013 at 10:22 PM, Stephen Jones <
lloydsystems at fastmail.com.au> wrote:

> Hi,
>
> A while ago I setup Samba4 on CentOS 6.  Samba version was 4.0.0 using
> the RPM from SOGo.  I used the DLZ BIND backend with BIND 9.8.
>
> I tested with a Windows 7 VM client.  When I joined the client to the
> domain it was automatically added to the AD DNS and appeared in the
> Windows DNS Manager.  The VM had a static IP, but if I changed the IP
> address that change was automatically reflected in the DNS entry.
>
> I am now adding new real clients to the domain and find that they are
> not added to the AD domain DNS.  The client has a dynamic IP, but I have
> tried changing to a fixed IP address and it makes no difference.
>
> The only changes I can recall between the initial setup and now are:
>
> 1. Samba upgrade to 4.0.1.  After upgrading I followed the procedure and
> ran
> samba-tool dbcheck --cross-ncs --fix
> samba-tool ntacl sysvolreset
> The upgrade changed the permissions of /var/lib/samba4/private back to
> root:root 700, which is no good, so I changed back to root:named 750.
> I also added "server services = -dns" to smb.conf as per the
> instructions because internal DNS is now default.
>
> 2. Tested OpenChange.  But, prior to doing anything I backed up entire
> /var/lib/samba4 directory.  When I removed OpenChange (as it is just not
> stable yet) I removed /var/lib/samba4 and replaced it with the backup.
> So this should not have any effect.
>
> I have checked everything against my notes made when installing Samba4
> and can't find anything wrong.  In terms of DNS, /etc/named.conf
> contains
> include "/var/lib/samba4/private/named.conf";
> which loads the DLZ module for BIND 9.8.
> The /etc/named.conf also has in the options
> tkey-gssapi-keytab "/var/lib/samba4/private/dns.keytab";
> Permissions of files:
> /var/lib/samba4/private/named.conf  root:named 640
> /var/lib/samba4/private/dns.keytab  root:named 640
> /var/lib/samba4/private/dns/  root:named 770
>
> It all seems OK (I think), but no dynamic DNS updates.  There is nothing
> in the samba.log file to suggest a problem.  The system log has messages
> client <IP address>: update 'example.local/IN' denied
> samba_dlz: cancelling transaction on zone example.local
>
> Is there something I need to set in smb.conf?  I see there are new
> options like "allow dns updates" and "dns update command", which I do
> not have specifically set, but I don't know if these only apply to Samba
> internal DNS.  There is still really no documentation about smb.conf for
> Samba4.
>
> Can someone please explain what might be wrong or what I should look
> for.
>
>
Hello Stephen,

I have been experiencing the same problem for the past month or so.
Unfortunately, I have been unable to find a solution. I was able to dig
back through my logs and found that the last DNS update occurred very early
in the morning, so for some reason it just stopped updating. You can start
bind in debugging mode "named -u named -g -d 5", then run "ipconfig
/registerdns" on the Windows client. If you see the following, then you are
experiencing the same issue:

28-Mar-2013 08:26:15.759 failed gss_inquire_cred: GSSAPI error: Major
= Unspecified GSS failure.  Minor code may provide more information,
Minor = Success.
28-Mar-2013 08:26:15.760 failed gss_accept_sec_context: GSSAPI error:
Major = Unspecified GSS failure.  Minor code may provide more
information, Minor = .
28-Mar-2013 08:26:15.760 process_gsstkey(): dns_tsigerror_badkey

This is not a problem with the internal DNS server, so that may be a
solution. Do be advised that MX and CNAME records are broken in the
internal DNS server, so that may not work for you. I'm working on migrating
everything to Windows Server in my test environment. Since there is no way
to go back to Samba 3, that seems to be the only option I have. Please let
me know if you see the same errors with named in debugging mode. Perhaps
it's a different problem altogether.

Regards,
>
> Stephen Jones
> --
>   Stephen Jones
>   lloydsystems at fastmail.com.au
>
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