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Azure AD Domain Services - auto assigned DNS vs VM IP address conflict?

Sid Merrett
Occasional Contributor

Hi,

New to Azure, so please bear with me...

I've created a new domain (registered a domain within Azure) and then activated AD Domain Services for that domain.

So far so good.

I have created a new VM which I want to join to the AD domain and use it to administrate/manage AD 

All good - I have a public IP address and an auto-assigned  private IP address = 10.0.2.4

 

I can RDP to the new VM via its public IP.

 

So next I have followed this guide to configure DNS settings for the AD Service 

https://docs.microsoft.com/en-gb/azure/active-directory-domain-services/active-directory-ds-getting-...

And in the portal I discover that there are 2x IP addresses available to configure for AD DNS and here's where it gets confusing:

DNS IP addresses available =

10.0.2.4

10.0.2.5

So the first 10.0.2.4 is the same as for my new VM - implying that this VM is a DNS server, which would be news to me as it is a vanilla, unconfigured VM - all I have done is successfully RDP to it.

So why is it sharing an IP address that is somehow associated with AD DNS in Azure?


I have also tried joining the VM to the domain - it fails. It is unable to communicate with/find a domain controller. 

 

Any ideas/suggestions what I am doing wrong or what to do about this odd DNS IP addresss conflict with the VM?

 

Thanks in advance