Re: [Samba] samba AD - bind - deleted DNS entries are not removed completely
- Date: Wed, 21 Nov 2018 19:20:54 +0100
- From: Kacper Wirski via samba <samba@xxxxxxxxxxxxxxx>
- Subject: Re: [Samba] samba AD - bind - deleted DNS entries are not removed completely
Since noone answered, I'll add some more information - maybe I'm unclear
about the nature of the issue?
I re-read samba wiki, especially about DNS management and I didn't find
any information pointing to such behaviour. I was deleting all entries
using windows DNS management console (which is in the sama wiki, so I
suppose it's supported)
I don't have unfortunately another AD environment to see if it's a bug
related to bind/samba or expected behaviour (a feature) and I'm really
hoping, that someone could share if they ever ran into the same
behaviour when using BIND as backend (deleted dns records not being
fully deleted, retaining all windows ACL, including original entry-owner
and therefore disallowing any dynamic updates for this record - throwing
"insufficient rights" error).
W dniu 20.11.2018 o 23:56, Kacper Wirski via samba pisze:
I've posted about this issue some time ago, but I maybe didn't explain
myself enough and/or didn't supply enough information.
My setup is centos 7.5 samba 4.8.4 AD DCwith BIND as dns backend.
I noticed that some windows clients stopped doing secure dns dynamic
updates because of insufficient rights error.
Upon further digging I realized that all of the entries, that were not
able to be updated, are entries that existed some time in the past
(used by other hosts - in forward or IP's -in reverse and later on
were for whatever reason deleted.
That doesn't seem right to me, that deleted DNS entry is - somewhere
(where?) kept back and blocks new entry to be added, even though with
same A record or PTR IP addr.
i added windows host to domain with hostname "PC-1", it created
dynamic dns A record (PC-1 - <some-ip-address>).
I deleted this entry (using windows dns management console), removed
"PC-1" from domain, added another host with same name (PC-1).
Obviously it was a new member so new SID was generated.
Even though DNS entry was deleted, new "PC-1" host was nable to
dynamically add entry, because - even though deleted - samba still
"knew" about the deleted entry, which still had as owner previous
"pc-1". How do I know this?
I manually then re-added "PC-1 <-whatever IP> A record to forward
zone. And upon inspecting security TAB it had as owner unresolved sid
number - the exact SID of the deleted original PC-1 host. That
completely blocked new host with PC-1 hostname to dynamically update
it's DNS entry
All DNS managing was done via windows DNS mmc - maybe it's the culprit?
That overall doesn't sound right. Shouldn't removed DNS entries be
just that - removed? I restarted named, samba, did tombstone expunge
with lifetime =0 etc.. I'm not sure how to treat this? Is this a bug?
Expected behaviour? How can I then fix this? I'd rather not have to
add manually records and change owners. It's not the biggest deal in
forward zone, but it's much worse for reverse zone. E.g. recently I
replaced a lot of PC's, all of them got new host names, but they kept
IP's that belong to old, so now my reverse zone is mostly empty,
unless I start manually adding entries - which I'd rather not to.
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