[Samba] Cleanup after demoting an offline DC

[Rowland Penny]

On Fri, 5 Jan 2024 11:41:45 +0100
Thorsten Marquardt via samba <samba at lists.samba.org> wrote:

> Hi,
> 
> I demoted an outdated and offline DC following to: 
> https://wiki.samba.org/index.php/Demoting_a_Samba_AD_DC
> 
> Everthing appears to work well but there is still one, perhaps minor, 
> question regarding to the dns SOA-record:
> 
> The zone _msdcs.samdom.example.com still lists the demoted server in
> the SOA record.
> 
> Is it ok to manually change it to fsmo holder dc or an other dc?

You may not have to, AD dns is multi-master, which means that every DC
is the SOA. It all depends on which DC is the first nameserver in
/etc/resolv.conf

For instance on a Linux client with 192.168.1.2 (rpidc1) as the first
nameserver, I get this:

host -t SOA _msdcs.samdom.example.com
_msdcs.samdom.example.com has SOA record rpidc1.samdom.example.com. hostmaster.samdom.example.com. 114 900 600 86400 3600

Whilst on a DC (that is using itself as its first nameserver), I get
this:

host -t SOA _msdcs.samdom.example.com
_msdcs.samdom.example.com has SOA record tmpdc1.samdom.example.com. hostmaster.samdom.example.com. 114 900 600 86400 3600

If your old demoted DC is still in the SOA record, you probably only
need to delete it.

Rowland