[Samba] Problem with demoting, new dc and replic

[Rowland Penny]

On Thu, 17 May 2018 13:11:36 -0400
lingpanda101 via samba <samba at lists.samba.org> wrote:

> On 5/17/2018 12:45 PM, Carlos Bordon via samba wrote:
> > Hi!
> >
> > i have 3 dcs with samba
> >
> >
> > i demote bdc and replace it with dc2 with de same ip
> >
> > the replicate with dc1 is ok, and the replicate of dc3 with dc1 is
> > ok,
> >
> > the problem is in dc2 with dc3
> >
> > i found the problem, but i dont known how fixes
> >
> > when i do samba-tools drs showrepl in dc3
> >
> > i see in connection appears the old dc named bdc and dont appears
> > the new, dc2
> >
> > i try with samba-tool drs replicate but nothing change
> >
> > any idea?
> >
> > thanks for exist!
> 
> It sounds like after demote Samba was not able to remove some
> lingering objects.
> 
> You should remove any entries with the name bdc in your DNS. Look in 
> your domain zone as well as _msdcs.cimg.local. Search all sub folders 
> (ie., _sites,_tcp ect.)I find its easier to use Microsoft DNS manager 
> for this.
> 
> Confirm in Active Directory Users and Computers that the DC bdc is 
> deleted from the 'Domain Controllers' OU.
> 
> Finally open Active Directory Sites and Services and expand 
> 'Default-First-Site-Name'. Delete the bdc server if it exists. Expand 
> dc1 and dc3 and remove any 'automatically generated' site links 
> referencing bdc if they exist.  Use cation and double check before 
> deleting that it's bdc you are deleting.
> 
> Finally let the other DC's replicate the changes you made for a few 
> minutes. It should be relatively instant but just to be sure wait.
> Then run '/samba/sbin/samba_dnsupdate' on dc2.
> 
> 
> -James

Apart from the possible 'bdc' records in AD, I don't think you have a
replication problem. I say possible 'bdc' records, because they could
be tombstones and you cannot easily delete them.

Coming back to the replication, from what you have posted, you have this
topology:

         Matriz site        Filail site
            DC1 --------------- DC3
             |
             |
            DC2  

You don't actually want replication between DC2 & DC3, this would
mean using the WAN link. DC2 would replicate to DC1 (and
visa versa), DC1 would replicate to DC3 (and visa versa again).

Rowland