Reverse DNS zone incorrect Name servers

garethlee · 2025-07-07T14:00:10.685Z

Hi

Our DNS seems to work absolutely fine, we don’t see any issues and the DCDIAG tests come back with no issues.

However the reverse lookup zones aren’t populating all our subnets and the ones that are listed have name servers that dont exist. These name servers are going back before I started so I want to tidy them up etc

They are somewhere in AD I believe..

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We have some that are listed here which are fine the others “unknown” should of gone years ago

Looked through ADSI edit and cant see any trace…but may of missed it !

Can anyone point us in the right direction

Thanks

Jay-Updegrove · 2025-07-07T14:10:46.493Z

Check your firewall, see if a previous admin set things up in an unexpected place. I found the majority of our subnets there, instead of Windows DNS. Also, if you have a switch manager (like UniFi or Meraki, for example) check there as well…you might be surprised!

garethlee · 2025-07-07T14:27:08.485Z

Checked firewall and nothing there..but I shall check again !
No switch manager in use …
These reverse lookups are all AD integrated if that helps

matt7863 · 2025-07-07T15:26:54.119Z

just edit the wrong ones and update the server.
For any missing just create them.

Common practice is to just create supernets such as 10.0.0.0/8 and 192.168.0.0/16 and then they will populate for any more specific matching subnets.
If you do that and they are working you could then delete the existing specific ones.

Rod-IT · 2025-07-07T16:19:40.851Z

Look at your event logs on your DCs, you’ll see why reverse DNS is failing to be created.

As @matt7863 noted, I expect your zone doesn’t cover those subnets for the PTR.

garethlee · 2025-07-08T06:08:04.908Z

Hi
I suspect your right but the thing thats bugging me is where are these DNS servers held in AD I cannot find them for love nor money !

They are coming from somewhere as no one would of even knew about these old boxes. But here they are !

I could wipe the name servers out and manually enter the correct ones …but finding these incorrect ones in AD is my 1st task.

I couldnt see anything in the logs last time out im on it again today
cheers