[Samba] Server GC/name.dom/dom is not registered with our KDC: Miscellaneous failure (see text): Server (GC/name/dom at DOM) unknown

Sven Schwedas sven.schwedas at tao.at
Fri Sep 8 12:40:09 UTC 2017

On 2017-09-08 10:37, L.P.H. van Belle wrote:
> Hai Sven, 
> Sorry for the long wait, i had some things todo first here.

's fine. It's not like I don't have other stuff to worry about either.

>> -----Oorspronkelijk bericht-----
>>>>> I suggest the following, move fsmo roles to villach-dc and
>>>> check database replications.
>>>> DB replication is already spewing errors, what am I to 
>>>> look out for?
>>> Ok, get my check db script, run it from any dc. And post me 
>>> the output. 
>> Output attached. Seems like all servers but graz-dc-sem have 
>> some stuff wrong, just wonderful.
> Ok base on the log, 
> graz-dc-sem.ad.tao.at is the most complete/correct server. 

And also the one with the keytab problems. :(

>>>>>>> Then remove a failty server and re-add it as a new installed DC.
>>>>>>> ( the good DS with FSMO)
>>>>>>> First backup: /var/lib/samba/private/secrets.keytab
>>>>>>> Remove the incorrect entries from keytab file with ktutil rkt 
>>>>>>> /var/lib/samba/private/secrets.keytab
>>>>>>> list -e -t
>>>>> Start with the keytab cleanup
>>>>> Check the dns record if the uuid A PTR and hostnames
>>>>> resolve to the correct server. 
>>>>> If thats the case, then no, cleanup of keytab is, i think,
>>>>> sufficient. 
>>>> Just to confirm the order: Clean up the keytab, if that 
>>>> doesn't work, 
>>>> start removing servers?
>>> Almost. Backup then ...   Cleanup keytab of the server. 
>> I'll try that next, unless you find something shady in the report.

While going through the records with Directory Studio I noticed that the
duplicate keytab entries are mirrored by servicePrincipalName entries in
CN=GRAZ-DC-SEM,OU=Domain Controllers,DC=ad,DC=tao,DC=at

Which should I clean up, and in what order? LDAP first, then keytab?
Just LDAP?

>>>> First message on that topic:
>>>> https://lists.samba.org/archive/samba/2017-March/207429.html
>>> Ok, this one, track down both uuid's, checkout which which 
>>> hostname belongs with these.
>> Going by the output of `samba-tool drs showrepl` and sam.ldb, 
>> the GUIDs are as follows:
>> graz-dc-sem	160f5a53-5c29-4a83-aeee-6cb1dbabeed7
>> graz-dc-bis	7e4973ba-4093-4523-a70f-7caa4845e34d (not in sam.ldb)
>> graz-dc-1b	bcffbad8-1add-46b9-bf69-90e52c0f09ea
>> villach-dc-sem	eb5f9772-cd8f-4cde-9629-f1898c94aedd
>> villach-dc-bis	e1569c90-50f9-4bb5-bd85-79145e3ff6fd
>> villach-sem/bis want to replicate to the dead and removed 
>> graz-dc-bis for some reason, but don't have its GUID in their 
>> sam.ldb either.
> Ok, can you do a manualy check on graz-dc-sem and villach-dc-sem 
> Both command on each server. 
> samba-tool dbcheck 
> And 
> samba-tool dbcheck --cross-nc 
> Error, post them. 

About that… villach-dc-sem is down because its VM host went poof
yesterday. :/ Gonna get it repaired at some point next week.

On graz-dc-sem, samba-tool dbcheck shows zero errors. --cross-nc gives:

> Error: governsID CN=ucsUser,CN=Schema,CN=Configuration,DC=ad,DC=tao,DC=at on already exists as an attributeId or governsId
> Error: governsID CN=taoSharedFolder,CN=Schema,CN=Configuration,DC=ad,DC=tao,DC=at on already exists as an attributeId or governsId
> Error: governsID CN=taoMailingList,CN=Schema,CN=Configuration,DC=ad,DC=tao,DC=at on already exists as an attributeId or governsId

Those are presumably from me fucking around with custom LDAP attributes
years ago and don't seem to be related. I hope.

>>>>>  – I noticed a typo in the server's `netbios name` 
>> setting, corrected it, and restarted the DC. 
>>> 3. Yes, for the new hostname, the old hostname is as left 
>> over in the ADDC DB and/or DNS. 
>>> This name GRAZ-DC-BIS, and the name with the typo. The GUID 
>> for these is where to look info. 
>> Yeah, but where?
> Now this is here ApacheStudio is very handy, but again, dont rush things here. 
> With ApacheStu.. Connect to the AD, and search for the faulty GUID/UUID's 
> Same for the hostname. 
> Ow did i tell you to make a backup first..  ;-) make it 2. ;-) 

No results for either the old name, nor the new name, nor the GUID, on
any server.

How is `drs showrepl` giving me the UUID for something that's nowhere in

> Now, last, which is an option. 
> If one server hold a good and correct database, you can sync that one to the other servers. 
> But the database must be correct. ( and backuped 2 x ) 


1. Back up graz-dc-sem
2. purge the duplicate keytab/SPN magic voodoo somehow (see above)
3. Force sync?

> samba-tool dbcheck --help gives also few extra options but i never used them so i cant tell much of these are usefull. 
>   --reindex             force database re-index 
>   --reset-well-known-acls
>   --cross-ncs  

Mit freundlichen Grüßen, / Best Regards,
Sven Schwedas, Systemadministrator
Mail/XMPP sven.schwedas at tao.at | Skype sven.schwedas
TAO Digital | Lendplatz 45 | A8020 Graz
https://www.tao-digital.at | Tel +43 680 301 7167

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