Bug 13502 - Can't update DNS entry from RODC
Summary: Can't update DNS entry from RODC
Status: NEW
Alias: None
Product: Samba 4.1 and newer
Classification: Unclassified
Component: DNS server (internal) (show other bugs)
Version: 4.7.4
Hardware: All All
: P5 normal (vote)
Target Milestone: ---
Assignee: Kai Blin
QA Contact: Samba QA Contact
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2018-07-02 12:51 UTC by Jean-Sébastien Bevilacqua
Modified: 2020-03-11 09:49 UTC (History)
3 users (show)

See Also:


Attachments
Error log 1 (6.63 KB, text/x-log)
2018-07-02 12:51 UTC, Jean-Sébastien Bevilacqua
no flags Details
Error log 2 (4.71 KB, text/x-log)
2018-07-02 12:52 UTC, Jean-Sébastien Bevilacqua
no flags Details
Succession of calls to samba_dnsupdate, showing non-updates entries (18.97 KB, text/plain)
2018-10-10 14:06 UTC, Julien ROPÉ
no flags Details

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Description Jean-Sébastien Bevilacqua 2018-07-02 12:51:55 UTC
Created attachment 14268 [details]
Error log 1

Hello,

When I try to update DNS entries from my RODC, I got error (in my_rodc_error.log attachment).
Moreover, my client tried to do the same and he got another error (client_rodc_error.log).

That's strange because if you manually add the DNS entry, it works well.

Sincerely,
Jean-Sébastien BEVILACQUA
Comment 1 Jean-Sébastien Bevilacqua 2018-07-02 12:52:15 UTC
Created attachment 14269 [details]
Error log 2
Comment 2 Julien ROPÉ 2018-10-10 14:06:27 UTC
Created attachment 14526 [details]
Succession of calls to samba_dnsupdate, showing non-updates entries


 Hi,

 I am working on this issue, and found the following :

 Environment:
  Domain: mondomaine.lan
  Sites:
  - Default-First-Site-Name (associated to subnet 192.168.56.0/24)
  - Secondary (associated to subnet 192.168.57.0/24)
  Domain controllers:
  - sambarwdc - DC - on site "Default-First-Site-Name"
  - sambarodc - RODC - on site "Secondary"


 After joining the domain as an RODC, when I run the "samba_dnsupdate" command, the RODC makes the "failed DNS update" errors reported above, associated to a timeout error.
 But if you check those entries (using "host -t SRV [entry]"), they will actually be found.

 Yet if you call "samba_dnsupdate" again, there are two entries that keep being updated - and this is repeatable each time you run the command.
 Those are
  _gc._tcp.Secondary._sites.mondomaine.lan
 _ldap._tcp.Secondary._sites.gc._msdcs.mondomaine.lan

 Testing those two entries show that they are effectively not registered in the DNS.

 The log attached shows the following sequence:
 - samba_dnsupdate right after joining as an RODC
 - several new calls to show the same entries being updated
 - verifying the entries are not found using "host -t SRV"

 I feel that the initial failure due to Timeout are actually not a bug - maybe the timeout is too short, but apparently the update succeeds in the end, so it's not really an issue.
 Now for the two entries that keeps being updated - even though no error are shown when we update them - this is a concern.

 Why are those updates failing? Is there something we can do to fix that, or is it a bug?

 Any advice is welcome to troubleshoot this.

 Regards,
 Julien