Assistance Required: Internal DNS Configuration Post-Azure Migration

Hi All,

We have successfully migrated all our servers to Azure and are now focusing on transitioning our internal domain DNS. While we continue to use our domain servers for Active Directory (rather than Azure AD), these servers have also been migrated to Azure. The final step is to demote and decommission the on-premise domain servers. However, these on-premise servers are currently serving as internal DNS servers for our domain.

We have enabled DNS services on the new Windows domain controllers in Azure, but DNS resolution is currently only occurring on one of the Azure servers. Both servers are operational, but failover does not occur when one goes down.

My questions are as follows:

• Are we configuring DNS correctly under this setup, or are we following an outdated approach?
• Should we consider alternative best practices for DNS management after migration?
• Why are the Azure DNS servers not failing over as expected? All on-premise clients have the two Azure server IPs configured for DNS, so they should be able to see and use both, as they did previously with the on-premise DNS servers.

For reference, we are connected from our on-premise environment to Azure via an ExpressRoute connection.

Thank you for your assistance.

Best regards, John