[Samba] Running smbd 4 + nmbd 3?

[Lou]

On Thu, Mar 11, 2021 at 09:56:39PM +0000, Rowland penny via samba wrote:
>No, you must use the nmbd that comes with Samba 4, the problem is that 
>you will have to use SMBv1 at both ends. This is not really a problem, 
>it is just a bit insecure and you might not need to run nmbd. It might 
>help if you can describe your setup in more detail and if you have 
>anything that must use SMBv1 (something that will not work without 
>SMBv1).

Thanks for the reply.

I have two servers:

smbd-server -> provides file sharing and runs smbd 3.6.25
nmbd-server -> it is the PDC and runs nmbd < 3.6.25

At smbd-server, smb.conf has the following line:

wins server = openldap.ufabc.int.br

So, nmbd that runs in nmbd-server, so nmbd-server runs as a wins server.  It
uses LDAP as a backend.

I need to enable latest protocols (SMB3+) for smbd-server

Alternatives I thought about:

1. Upgrade everything to Samba 4 as an AD DC.  This is not a good choice for
now, because I'd have to change the whole organization structure.

2. Upgrade everything to Samba 4, but do not "enable AD".  Make it use our LDAP
backend, so the change would be invisible to the clients.

3. Upgrade only smbd to Samba 4 and make it use the old nmbd at nmbd-server as
a wins server.  I tried it but I had no success.

I'd prefer go for 3, and then 2, and then 1, if it is possible.  Any
recommendations?

Thanks.