[Samba] Network rebuild advice needed

Rowland penny rpenny at samba.org
Mon Aug 17 06:39:14 UTC 2020

On 17/08/2020 04:21, Peter Pollock via samba wrote:
> So I screwed up my AD.
> At some point a Windows 2019 server was attempted to be added and it messed
> the schema up.
> That server was removed and ceremonially burned in the fire pit but I
> couldn't fix the issues that had arisen, so I restored both of the original
> Samba DC's from backups

That is probably where your main problems start, you should never 
restore an individual DC, you only restore a domain. You restored two 
DC's from backups, were the backups taken at exactly the same time ?

What you should have done was, restore one DC, seize all FSMO roles to 
this DC, forcibly demote any other DC's and then clean up the other DC's 
and rejoined them to the domain as new DC's

> and everything LOOKS OK on the surface, but they're
> not replicating and for some reason some of the permissions on the drive
> containing the home folders got changed even though the restore had nothing
> to do with that drive... and there are other weird issues, like the windows
> computers trying to log on randomly say there is no trust relationship
> between them and the domain.
> It's all weird and I can't work out how to fix any of it.
> I built a new DC (DC3) and that initially got a copy of everything from one
> of the original DC's but after that they won't replicate to it. It can
> replicate outbound with both of the other DC's but not inbound and DC1 and
> DC2 won't replicate with each other at all.
> We are a small school and have virtually zero budget (latest DC is built on
> an old desktop, so it can't stay around forever) but I've managed to get
> funding for a new server, which might help.
> One of my big problems is that we only have (or had) 2 servers. I couldn't
> risk not having a backup DC so I built them both as samba DC's - but one is
> also the fileserver. (I know, fileserves shouldn't be DC's but I didn't
> have much choice).
> I don't know how to fix the problems and have decided I probably need to
> rebuild both of the problem servers from scratch, but my understanding is
> that if I do that, I have to demote them then rebuild them with different
> names so the AD doesn't get confused. Is that right?
You can re-use the names, but you must ensure the DC is fully demoted 
and cleaned up before the join.
> My issue there is the shares on the fileserver. All the windows drive
> mappings on the client machines are to \\dc02\sharename  - and they won't
> work any more if I rebuild with a different server name. Is there a way to
> migrate them across?
> My fear is also that there is something screwy with the schema even now and
> just rebuilding won't fix that so I'm wondering if I should start again
> from scratch with a completely new domain, somehow import all the user
> details and go around manually rejoining all the workstations.
If you have a backup from before the Windows 2019 DC was joined, you 
should be able to fix this, but you will lose any changes made to AD 
after the backup was made.
> I'm looking for advice here. I know I've messed up bad but I have to try to
> fix it, although that's hard because now school is back in session I can't
> do anything during the day, partly because I'm teaching and partly because
> the teachers rely on the network for their teaching. I'm going to take the
> school offline in a couple of weeks for an entire weekend to fix this
> nonsense... I just don't know what the best way to go about fixing it is?

It sounds like you now have three machines to use, perhaps use one as a 
Unix domain member running as a fileserver and the other two as DC's.


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