[Samba] Demote a dead PDC: residuals in "DNS" console

James lingpanda101 at gmail.com
Thu Oct 29 13:37:36 UTC 2015 

On 10/29/2015 9:15 AM, Ole Traupe wrote:
>
>
> Am 29.10.2015 um 13:54 schrieb mathias dufresne:
>> Thank you for hint to this VBS script. In fact I alraedy saw it but 
>> I'm not
>> too confident in my VB knowledge, so I didn't use that script, prefering
>> rely on Samba command and shell scripts to work around issues.
>>
>> You spoke about SOA record which wasn't changed, same here. There is
>> another DNS record I had to change: 
>> _ldap._tcp.pdc._msdcs.samba.domain.tld.
>
> Yes, I can confirm that I had to change that one, too.
>
>>
>> I spoke about removing removed-DCs from sites and the command to do that
>> could be:
>> ldbdel -H $sam -b 'cn=sites,CN=Configuration,DC=samba,DC=domain,DC=tld'
>> CN=removed-DC,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=samba,DC=domain,DC=tld 
>>
>> Deleted 1 record
>>
>> To get list of all contents in sites:
>> ldbsearch -H $sam -b 
>> 'cn=sites,CN=Configuration,DC=samba,DC=domain,DC=tld'
>> cn=* dn
>>
>> This will list all entries in "sites" container.
>>
>> Looking
>> into 
>> CN=Servers,CN=Default-First-Site-Name,cn=sites,CN=Configuration,DC=samba,DC=domain,DC=tld
>> ldbsearch -H $sam -b
>> 'CN=Servers,CN=Default-First-Site-Name,cn=sites,CN=Configuration,DC=ad,DC=dgfip,DC=finances,DC=gouv,DC=fr' 
>>
>> cn=* dn
>>
>> There are 4 entries in that container per declared DC in the site. 
>> Only the
>> one mentioned earlier had to be removed manually, the three others 
>> should
>> have been removed during demote process as I didn't removed by myself 
>> and
>> they weren't present before I manually perform mentioned clean up.
>
> Thank you for the further details. I can't really say anything about 
> these entries or commands. There was only one entry in the ADSS 
> console for my former PDC, and the script got rid of that.
>
> Best,
> Ole
>
>
>>
>> Cheers,
>>
>> mathias
>>
>>
>> 2015-10-29 12:38 GMT+01:00 Ole Traupe <ole.traupe at tu-berlin.de>:
>>
>>> Hi mathias,
>>>
>>> thanks for the heads-up! However, my AD Sites and Services is clear, 
>>> too.
>>> I followed the suggestion here
>>> https://wiki.samba.org/index.php/Demote_a_Samba_AD_DC
>>> to use this
>>>
>>> http://gallery.technet.microsoft.com/scriptcenter/d31f091f-2642-4ede-9f97-0e1cc4d577f3#content 
>>>
>>> script.
>>>
>>> Copy the contents of the "Visual Basic" box to a text file and 
>>> rename it
>>> to "something.vbs". Run the vb script as admin e.g. on a Win 7 64 bit
>>> (worked for me) domain member client being logged on as 
>>> "Administrator".
>>> This removed my former PDC from ADUC and ADSS.
>>>
>>> Best,
>>> Ole
>>>
>>>
>>>
>>> Am 29.10.2015 um 12:16 schrieb mathias dufresne:
>>>
>>>> Hi,
>>>>
>>>> I played with demote recently on a test AD domain composed with Samba
>>>> version 4.3.0 and 4.3.1. I demoted all version 4.3.0.
>>>>
>>>> I was facing same issue as you. I written long mails here to 
>>>> explain how I
>>>> managed that. My DNS looks clear now.
>>>>
>>>> Today I played with AD sites and I found in default sites all 
>>>> demoted DC.
>>>> They weren't removed from DNS DB nor here. For now I have no idea 
>>>> how to
>>>> get rid of these DC in my sites configuration without ADUC.
>>>>
>>>> So you should have a look into your AD Sites configuration tool to 
>>>> check
>>>> if
>>>> they were correctly removed.
>>>>
>>>> Cheers,
>>>>
>>>> mathias
>>>>
>>>>
>>>> 2015-10-29 10:01 GMT+01:00 Ole Traupe <ole.traupe at tu-berlin.de>:
>>>>
>>>> Ok, I made a backup following the Samba wiki and then did this. Had to
>>>>> wait a bit between updating the SOA's because I got a strange error
>>>>> message
>>>>> saying that a time value for the non-update of some resource cleanup
>>>>> wasn't
>>>>> set. But a few minutes later I could update the second SOA as 
>>>>> well, and
>>>>> now
>>>>> the Samba log is clean.
>>>>>
>>>>> Ole
>>>>>
>>>>>
>>>>>
>>>>> Am 28.10.2015 um 16:42 schrieb Ole Traupe:
>>>>>
>>>>> Hi,
>>>>>> I demoted my PDC (DC1) forcefully, because replication (among 
>>>>>> others)
>>>>>> wasn't working anymore due to hard disk failure and I was afraid of
>>>>>> spending a lot of time on nothing.
>>>>>>
>>>>>> With DC1 offline I seized the FSMO roles on DC2 (4.2.5), restarted
>>>>>> Samba,
>>>>>> and found errors in the samba log due to the missing DC1.
>>>>>>
>>>>>> I removed the two DNS entries created according to this site:
>>>>>> https://wiki.samba.org/index.php/Check_and_fix_DNS_entries_on_DC_joins 
>>>>>>
>>>>>> I applied the script suggested here:
>>>>>> https://wiki.samba.org/index.php/Demote_a_Samba_AD_DC
>>>>>> This removed the DC1 entry in ADUC and "Active Directory Sites and
>>>>>> Services".
>>>>>>
>>>>>> However, the error persists (10 minute interval; sanitized):
>>>>>> # /usr/local/samba/sbin/samba_dnsupdate: couldn't get address for '
>>>>>> dc1.my.domain.de': not found
>>>>>>
>>>>>> Likely due to further DNS entries, the last-mentioned site 
>>>>>> suggests to
>>>>>> remove them by hand. Most of the containers in the DNS console 
>>>>>> have only
>>>>>> duplicate entries for DC1/2, so no problem. However, 3 don't:
>>>>>>
>>>>>>
>>>>>> (removed subfolder and client PC entries; sanitized, translated 
>>>>>> where
>>>>>> necessary GR->EN)
>>>>>>
>>>>>>
>>>>>> *DNS/DC2/Forward-Lookupzones/my.domain.de*
>>>>>>
>>>>>> Name    Type    Data    Time stamp
>>>>>> (identical to parent folder)    Source of Authority (SOA)    [3],
>>>>>> dc1.my.domain.de., hostmaster.my.domain.de. ?28.?10.?2015 15:00:00
>>>>>> (identical to parent folder)    Nameserver (NS) dc1.my.domain.de.
>>>>>> Static
>>>>>> (identical to parent folder)    Host (A) IP__of__DC1    Static
>>>>>> (identical to parent folder)    Host (A) IP__of__DC2    Static
>>>>>> DC2    Host (A)    130.149.34.118    ?29.?07.?2015 13:00:00
>>>>>>
>>>>>>
>>>>>> *DNS/DC2/Forward-Lookupzones/_msdcs.my.domain.de*
>>>>>>
>>>>>> (identical to parent folder)    Source of Authority (SOA)    [3],
>>>>>> dc1.my.domain.de., hostmaster.my.domain.de. ?28.?10.?2015 15:00:00
>>>>>> (identical to parent folder)    Nameserver (NS) dc1.my.domain.de.
>>>>>> Static
>>>>>> objectGUID__of__DC2    Alias (CNAME) DC2.my.domain.de. ?29.?07.?2015
>>>>>> 13:00:00
>>>>>>
>>>>>>
>>>>>> *DNS/DC2/Forward-Lookupzones/_msdcs.my.domain.de/pdc/_tcp*
>>>>>>
>>>>>> _ldap    Service Identification (SRV)    [0][100][389] 
>>>>>> dc1.my.domain.de
>>>>>> .
>>>>>>     Static
>>>>>>
>>>>>>
>>>>>> What to do in these cases? Is it safe to open the properties of the
>>>>>> non-duplicate entries and replace DC1 with DC2?
>>>>>>
>>>>>> Ole
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> -- 
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>>>>>
>>>>>
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>>>
>
>
When I demoted DC's in the past. I used ADSS, ADUC and ADSI to delete 
all traces. ADSI was necessary to delete all NTDS traces. This was on 
Samba 4.0.X versions. I take it you have no replication issues pointing 
to the old DC either?

-- 
-James

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