samba - Mar 2020 - samba_dnsupdate

On 02/03/2020 09:54, Paul Littlefield via samba wrote:
> Hello,
>
> I have some DNS weirdness for you folks to chew on and help me with...
>
> On Saturday I added this entry...
>
> $ samba-tool dns add dc3 mydomain.com V-RDS02 A 130.130.0.252
>
> but this morning I've come in to the office and the A records have 
> disappeared to be replaced by AAAA records...
>
> ...so no-one can get to where they need to be.
>
> I add the A record back in to the DNS...
>
> What is causing this?
Does your DC have a fixed IP and if not, why not ?

Rowland

On 02/03/2020 10:49, Rowland penny via samba wrote:
> Does your DC have a fixed IP and if not, why not ?
Yes, using netplan in Ubuntu 18.04...

network:
   ethernets:
     ens18:
       addresses:
       - 130.130.0.218/16
       gateway4: 130.130.0.1
       nameservers:
         addresses:
         - 130.130.0.218
         - 130.130.0.219
         search:
         - mydomain.com
       optional: true
   version: 2



It's just happened AGAIN... the main servers A records have gone and
replaced by IPv6 ones.

I'm using the Samba 4 Internal DNS and ISC DHCP Server and have
'ddns-update-style none;' in the DHCP server config.

Questions...

1. How do I turn on Samba 4 AD DC logging for DNS updates?

2. Can I watch for DNS requests in tcpdump?

3. I have another DC which is replicating fine with this DC and after I have
REMOVED the AAAA IPv6 entries + ADDED the A records in _either_ DC it lasts for
a while then they get removed again!


Paully

On 02/03/2020 11:51, Paul Littlefield via samba wrote:
> On 02/03/2020 10:49, Rowland penny via samba wrote:
>> Does your DC have a fixed IP and if not, why not ?
>
> Yes, using netplan in Ubuntu 18.04...
>
> network:
> ? ethernets:
> ??? ens18:
> ????? addresses:
> ????? - 130.130.0.218/16
> ????? gateway4: 130.130.0.1
> ????? nameservers:
> ??????? addresses:
> ??????? - 130.130.0.218
> ??????? - 130.130.0.219
> ??????? search:
> ??????? - mydomain.com
> ????? optional: true
> ? version: 2
Samba runs samba_dnsupgrade on a regular basis, using dns_update_list as 
a template. Amongst the list of dns entries is this:

AAAA ${HOSTNAME}?????????????????????????????????????????? $IP
>
>
>
> It's just happened AGAIN... the main servers A records have gone and 
> replaced by IPv6 ones.
I am unsure why it is doing this, I have never seen this happening, but 
then again I do not use IPv6 or netplan.
>
> I'm using the Samba 4 Internal DNS and ISC DHCP Server and have 
> 'ddns-update-style none;' in the DHCP server config.
>
> Questions...
>
> 1. How do I turn on Samba 4 AD DC logging for DNS updates?
add 'log level = 4' to the smb.conf on the DC
>
> 2. Can I watch for DNS requests in tcpdump?
I do not see why you couldn't.
>
>
> 3. I have another DC which is replicating fine with this DC and after 
> I have REMOVED the AAAA IPv6 entries + ADDED the A records in _either_ 
> DC it lasts for a while then they get removed again!
Fairly sure this is samba_dnsupgrade doing this, but why is another 
question.

Rowland