Exam AZ-802 Topic 1 Question 208 Discussion

Explanation:
On Vnet1 (VM1): configure VM1 to forward requests for the contoso.com zone to the Azure-provided DNS at 168.63.129.16. On the on-premises network: configure forwarding for the contoso.com zone to VM1.
The Azure-provided DNS resolver at 168.63.129.16 is what actually knows about the contoso.com private DNS zone, because that zone is linked to Vnet1 and platform DNS only answers private-zone queries for resources/clients located inside the linked virtual network; it cannot be queried directly by anything outside that VNet, including the on-premises network across the Site-to-Site VPN. VM1, however, sits inside Vnet1 and can reach 168.63.129.16 directly, so configuring VM1 ' s own DNS Server role to forward contoso.com queries to 168.63.129.16 lets VM1 successfully resolve private-zone records (and, transitively, records that depend on the public zone data for PaaS resources) on behalf of anyone who asks VM1. On the on-premises side, the on-premises DNS infrastructure has no direct path to the Azure platform resolver at all, so it must instead be configured to forward contoso.com queries to VM1 ' s IP address, which is reachable across the established Site-to-Site VPN. This produces a working chain: on-premises clients query their local DNS server, which forwards contoso.com queries across the VPN to VM1, which in turn forwards them to the Azure-provided DNS resolver that can actually see the linked private zone, and the resolved answer flows back along the same path. Configuring VM1 to forward to the public DNS zone directly, or configuring on- premises forwarding straight to 168.63.129.16 or to the public zone, would each skip a required hop and fail to resolve the private zone ' s records.