I have an active directory domain services role plus DNS installed in a Windows Server 2016 STD in a VM of Hypver-V with the domain name of xyz.net, The Hypver-V is hosted in physical machine of DELL PowerEdge R750 and I have 2 other additional domain controllers also which secondary additional domain controller is in same network subnet with primary domain controller location head office, but the 3rd Additional domain controller is in our DR site which is in a different network different location, but they are all sync with each other and has no issue.
The problem is whenever we down the primary and secondary domain controller for testing which are in same network the DNS traffic/queries are not going automatically to 3rd additional domain controller which we have in our DR site its pointing to head office primary domain controller.
I did ipconfig/flushdns and ipconfig/registerdns and did a restart of the client PC also waited for 5 minutes, but still whenever I was tracert our domain xyz.net it was pointing to primary DNS.
How to point automatically my clients DNS queries to 3rd additional domain controller when my primary and secondary domain controllers are down.
I have already added the DNS IPs in clients computer.