DNS Registration failing for workstations running in Azure?

Hi Kapil, yes I have read that we can now deploy DHCP servers, however in our case we do not have any DHCP servers deployed. The machine gets its IP from Azure DHCP (wireserver).

The IP is allocated correctly by Azure and everything works except for the re-registration. I believe it may be attempting to re-register to Microsoft public DNS servers instead of our private mydomain.local DNS servers, even though mydomain.local is set as the primary DNS suffix.

Perhaps of relevance is that we do have the following GPO enabled:

• Register DNS records with connection-specific DNS suffix
  Software\Policies\Microsoft\Windows NT\DNSClient\RegisterAdapterName = 1

however my assumption is that this would not cause any trouble because:

If you enable this policy setting, a computer will register A and PTR resource records with its connection-specific DNS suffix, in addition to the primary DNS suffix.

Ok, it looks like the 24 hour re-registration only applies to static IP addresses. The below can be found here but comes from the explain text in Group Policy for "Registration refresh interval":

By default, client computers configured with a static IP address attempt to update their DNS resource records once every 24 hours and DHCP clients will attempt to update their DNS resource records when a DHCP lease is granted or renewed.

Azure leases expire in 136+ years, so it seems that it is per-design that Windows will not re-register!

The answer would therefore seem to be that we have to explicitly schedule the updates via GPO, ie:

• Computer Configuration \ Network \ DNS Client \ Registration refresh interval
• Enabled

A value of 86400 seconds will cause Windows to re-register once per day as expected.

@Simon Gadsby ,

I have limited expertise on GPO however I am glad that you were able to resolve your issue and thank you for posting your solution so that others experiencing the same thing can easily reference this!

Since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others", I have summarized our discussion and post it as an answer.

I would greatly appreciate if you could Accept the answer and close this thread

Original posters help the community find answers faster by identifying the correct answer.

Thanks,

Kapil

That is fine Kapil however I can only see your original answer?

Also I am not 100% sure this is the resolution -- I wonder whether Windows may sometimes be attempting to register with the wrong DNS server (ie. Microsoft public DNS rather than my private DNS), therefore forcing the re-register interval with GPO might just mask the issue by running it more often such that it is more likely to work!

@Simon Gadsby ,

To get more clarity on Windows Configuration and GPO, you can consider creating a new thread with the appropriate tags, so that the community experts can address it.

I am afraid my expertise with GPO is limited as mentioned.

Wrt, "I wonder whether Windows may sometimes be attempting to register with the wrong DNS server (ie. Microsoft public DNS rather than my private DNS),"

• I am not sure why you would have this observation.
• The Windows machines in Azure, should use whatever DNS Servers you specified in the VNET Configuration as the DNS Server.
• See : Change DNS servers of a virtual network using the Azure portal
• And as long as DHCP settings is configured correctly, the VMs should use the appropriate DHCP servers

Cheers,

Kapil