[Samba] DNS problem ubuntu server 20.04

[Rowland penny]

On 15/05/2020 15:29, L.P.H. van Belle via samba wrote:
>   
>
>> -----Oorspronkelijk bericht-----
>> Van: samba [mailto:samba-bounces at lists.samba.org] Namens
>> Rowland penny via samba
>> Verzonden: vrijdag 15 mei 2020 16:05
>> Aan: samba at lists.samba.org
>> Onderwerp: Re: [Samba] DNS problem ubuntu server 20.04
>>
>> On 15/05/2020 14:55, L.P.H. van Belle via samba wrote:
>>>> That is possible on a Unix domain member, but, in my opinion,
>>>> you would
>>>> have to remove systemd-resolve on a DC
>>>>
>>>> Run <sudo netstat -plnt | grep '53'> on a newly installed
>>>> Ubuntu 20.04
>>>> and you get this:
>>>>
>>>> tcp        0      0 127.0.0.53:53 0.0.0.0:*               LISTEN
>>>> 451/systemd-resolve
>>>>
>>>> This would interfere with the AD dns server.
>>>>
>>> No, that a wrong understanding in my optinion.
>>>
>>> Per example. The client requests.
>> On a client that doesn't run a separate dns server it will
>> work, I can prove this, but you can only run one server on port 53 on a Samba AD DC
>> and that server has to be either the internal dns server or Bind9. If
>> you have systemd-resolve running on a DC, you are not using the dns
>> server you think you are.
>
> I can run as much DNS servers on 1 system as long i have ip adresses and free ports.
> And pass every request to the next in line..
>
> Im not saying thats the way to do it but yes you can make that work.
>
>
> 127.0.0.53:53 => i pass these requests to 192.168.0.1:53 ( where samba-ad-dc runs )
> Just like any other caching server setup.
>
> I can make it also work like this.
>
> (127.0.0.53:53 sub => 127.0.0.1:53 bind9 caching) => 192.168.0.1:53 samba AD-DC dns.
>
OK, I have been thinking about this (yes I know, thinking, possibly 
dangerous), And yes, you could do that on a DC, but why ?

All your clients would use '192.168.0.1' for their nameserver and 
'127.0.0.53' and '127.0.0.1' would be ignored by the clients, or am I 
missing something.

Also, lets not forget we are talking about a DC , so if you cannot 
remove systemd-resolve and manually create /etc/resolv.conf, you have no 
place in setting up a Samba AD DC.

Rowland