Domain controller unable to dynamically add/update PTR record

Tue Jan 25 01:38:42 UTC 2005

Smith, William E. (Bill), Jr. wrote:

>In our environment, we have allowed Windows domain controllers to
>dynamically update their A & PTR records within the Windows only
>domains.  I'm currently troubelshooting a problem where a couple DC's
>register their A records fine but fail when trying to do their PTR
>records.  After sifting through the various server logs, I came across
>the following error which I believe is at the core of the problem since
>I had a Windows admin do an ipconfig /registerdns on the DC to force it
>to re-register its records and noted that this error appeared within
>seconds after that attempt.  
>update.log:Jan 24 11:45:24.901 info: client 128.244.198.27#2772:
>updating zone '
>dom1.jhuapl.edu/IN': update failed: 'RRset exists (value dependent)'
>prerequisit
>e not satisfied (NXRRSET)
>
>While it's clear that the problem is related to a prerequisite not being
>met, it's not clear to me what exact prerequisite has failed to be
>satisifed.  Can anyone shed any light here?  I know this is a common
>problem with DHCP clients but DHCP is not involved here.  FWIW, the
>primary DNS server where these updates are coming into is a QIP DNS
>server.  I'll provide any further info as needed/requested.
>
Hmmm... That's a failure of the *forward* update, because it would have 
been redundant (value-dependent NXRRSET). My guess would be that 
occurred when you manually did "ipconfig /registerdns" after the 
original failure, because, as you said, the forward update worked on the 
original try, just not the reverse update.

As for the root cause of why the reverse-record updates are failing, I 
would check the usual suspects, e.g. the appropriate allow-update 
statement on the reverse zone, correct info in the SOA record of the 
reverse zone, etc. What happens if you try to add a record to that zone 
via nsupdate?

                                       - Kevin