[Samba] Authentication to Secondary Domain Controller initially fails when PDC is offline

[mathias dufresne]

No idea about your main issue, I was merely answering to your last question
about changing SOA record.

Here is another view of that command:
samba-tool dns update <server> <zone> <name> SOA \
'OLDnameserver email serial refresh retry expire minimumttl' \
'NEWnameserver email serial refresh retry expire minimumttl'

I'm not too confident with DNS internals so I'm not sure if the TTL you
mentioned is or isn't "expire" or "minimumttl".

After digging a little bit it seems previous line is completely wrong,
neither "expire" nor "minimumttl" are "TTL".
This because :
dig -t SOA SAMBADOMAIN.TLD
...
samba.domain.tld. 1715 IN      SOA     DC1.samba.domain.tld. 62 900 600
86400 3600
...

And from what I just read in dig "ANSWER SECTION" the second field is the
TTL, so 1715 in my case, which as nothing to do with "expire" (86400) or
"minimumtll" (3600).

And that makes me wondering how TTL can be less than "minimumttl"...

So, the short way: the command I gave do not seem to be designed to help
you changing TTL. Sorry : )

Cheers,

mathias

2015-11-19 13:43 GMT+01:00 Ole Traupe <ole.traupe at tu-berlin.de>:

> Mathias, thank you very much for your comprehensive instructions!
>
> Just one question: Harry suggested that, in order to overcome the below
> DNS related problems, the TTL would have to be adjusted (lowered). However,
> the TTL seems to be the only time value not covered by the command provided
> by you.
>
> Is it really the TTL that is the culprit or is it rather the first time
> value (something like "Refresh value" in english)?
>
> Do you know this?
>
> Ole
>
>
>
> Am 19.11.2015 um 11:19 schrieb mathias dufresne:
>
> Hi Ole,
>
> You want to change SOA of your AD domain?
>
> Here some working command:
> samba-tool dns update <working DC> samba.domain.tld \
> samba.domain.tld SOA \
> 'oldSOA.samba.domain.tld. hostmaster.samba.domain.tld. 58 900 600 86400
> 3600' \
> 'newSOA.samba.domain.tld. hostmaster.saba.domain.tld. 59 900 600 86400
> 3600' -k yes
>
> This needs you performed some kinit before using an account able to modify
> this entry (by default only administrator is able to that I expect).
>
> This must be done for the two DNS zones of your domain:
> samba.domain.tld + _msdcs.samba.domain.tld
>
> First number of replacement record (here "59") is serial number.
> Replication of change seemed to work without changing that serial number
> but as DNS love to rely on it, changing that serial should be a good idea.
>
> Hoping this helps...
>
> Cheers,
>
> mathias
>
>
> 2015-11-18 16:44 GMT+01:00 Ole Traupe <ole.traupe at tu-berlin.de>:
>
>>
>> It is DNS related.
>>>
>>> What is the best way of dealing with this?
>>>>
>>> The *best way* is a HA solution for your DNS Servers, but its expensive.
>>>
>>> The DNS client (resolver) caches the srv records for 15 minutes aka 900
>>> seconds.
>>>
>>> ipconfig /flushdns drops the cache. Reboot does the same.
>>>
>>> On server side you may set shorter TTL for the server records, but then
>>> you have more DNS traffic. On small netwoks (sites up to 20 clients, no
>>> wifi) I have good experience with a TTL of 180.
>>>
>>
>> Harry, I tried this - unsuccessfully.
>>
>> I have TTL settings in a) the SOA and b) the NS record of the FQDN and
>> the _msdcs.FQDN sections in my Windows RSAT DNS console. None of these 4
>> entries I can change: I get something like "The Source Of Authority (SOA)
>> cannot be updated. The record already exists."
>>
>> Do you have an idea how to accomplish this? Currently the setting is 1h,
>> which is pretty long.
>>
>> Ole
>>
>>
>>
>>
>> --
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>
>
>