[Samba] Samba AD with multiple DC and multiple NICs

[Rowland penny]

On 19/10/2020 12:40, Stefano Vargiu via samba wrote:
> Hello everyone,
>
> I'm trying to add a second DC to a Samba 4 AD: they both have multiple NICs
> and for this reason cannot find a way to make it work.
> They communicate through VPN and both have one of the bound interfaces set
> to the same IP address, 172.20.0.1, which doesn't allow me to route to the
> correct DC, and that is only part of the problem.
>
> Here is the configuration:
> * DC1.domain.local
>    IP NIC1: 172.16.0.2
>    IP NIC2: 172.20.0.1
>    IP VPN: 172.19.1.173
>
> * DC2.domain.local
>    IP NIC1: 192.168.0.1
>    IP NIC2: 172.20.0.1
>    IP VPN: 172.19.1.174
>
I don't think you really understand dns and AD =-O

You cannot have two computers with the same IP (how would DNS 
differentiate between them), each DC is authoritative for the dns 
domain, this is called multi-master and means that each DC is the dns 
master. Each DC should use itself as its first nameserver and /etc/hosts 
is only used by the DC itself. You seem to be trying to use what is 
called multi-homed devices and this doesn't work very well (if at all) 
with AD. You shouldn't be trying to point VPN at your DC's, VPN should 
just use the DC's for authentication.

I think you need to explain just what you are trying to achieve and how 
you are doing it now.

Rowland