[Samba] Issues demoting a samba DC.

Michael Tokarev mjt at tls.msk.ru
Sun Jan 8 14:19:25 UTC 2023

08.01.2023 14:21, Rowland Penny via samba wrote:
>> ai# samba-tool domain demote -U mjt-adm
>> ERROR(ldb): Error while renaming CN=AI,OU=Domain Controllers,DC=tls,DC=msk,DC=ru to CN=AI,CN=Computers,DC=tls,DC=msk,DC=ru - LDAP error 50 
>> LDAP_INSUFFICIENT_ACCESS_RIGHTS -  <acl:access_denied renaming CN=AI,OU=Domain Controllers,DC=tls,DC=msk,DC=ru> <>
> If you get any errors whilst trying to demote a DC, then it is probably quicker to forcibly demote the DC on another DC, why waste time trying to fix 
> something you are trying to get rid of ?

The problem with this approach is that we don't know what's happening, and thus
unable to fix the bugs.

I removed this DC the "use the force" way, from another DC.
Turned it off for sure too, - so it wont get contacted by a chance.
Especially cleaned up all DNS caches from the old names as well.

But now I've a lot of messages on another DC's log.samba (the one
which now has FSMO roles):

[2023/01/08 17:10:55.689675,  0] ../../source4/librpc/rpc/dcerpc_util.c:681(dcerpc_pipe_auth_recv)
   Failed to bind to uuid e3514235-4b06-11d1-ab04-00c04fc2dcd2 for 

What is e3514235-4b06-11d1-ab04-00c04fc2dcd2 where it tries to bind to?

4b38bf02-0354-44f7-b1b2-4bc8bd73784a is the other DC's alias (svdcp vs svdcm):

# dnsget 4b38bf02-0354-44f7-b1b2-4bc8bd73784a._msdcs.tls.msk.ru
4b38bf02-0354-44f7-b1b2-4bc8bd73784a._msdcs.tls.msk.ru. CNAME svdcp.tls.msk.ru.
svdcp.tls.msk.ru. A

I haven't found the string e3514235-4b06-11d1-ab04-00c04fc2dcd2 anywhere in
/var/lib/samba/ or similar dirs, the only single mention of it is in

# These are not supported yet:
# NtFrs-88f5d2bd-b646-11d2-a6d3-00c04fc9b232/${HOSTNAME}
# Dfsr-12F9A27C-BF97-4787-9364-D31B6C55EB04/${HOSTNAME}

(yes, commented out).

What it is doing here?  It *looks* like this is being logged when the this DC
(msdcm) is trying to replicate to msdcp, - but that one reports successful
replication, while this one (svdcm) shows errors in replication:

	Pereslavl-Office\SVDCP via RPC
		DSA object GUID: 4b38bf02-0354-44f7-b1b2-4bc8bd73784a
		Last attempt @ Sun Jan  8 17:15:55 2023 MSK failed, result 1311 (WERR_NO_LOGON_SERVERS)
		12 consecutive failure(s).
		Last success @ Sun Jan  8 16:22:13 2023 MSK

I'm not sure this is how things are supposed to be... :)



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