Question

Your company runs a hub-and-spoke topology in Azure. VMs in the spoke VNets must resolve names for internal Azure resources, public internet names, and records hosted on an on-premises Active Directory DNS server (10.50.0.10) reachable over an ExpressRoute connection. You deploy a pair of DNS forwarder VMs in the hub VNet and want all spoke VMs to use them. Which configuration on the spoke VNets ensures VMs send DNS queries to the hub forwarders?

Accepted Answer

Set the spoke VNets' DNS servers to the private IP addresses of the hub forwarder VMs, then restart or reallocate the spoke VMs so they pick up the new setting.

Answer

Set the spoke VNets' DNS servers to 168.63.129.16 so Azure automatically relays queries to the on-premises DNS server.

Answer

Create an Azure Private DNS zone for the on-premises domain and link it to the spoke VNets with autoregistration enabled.

Answer

Configure a user-defined route in each spoke sending 10.50.0.10/32 traffic to the hub, which forces DNS resolution through the forwarders.