I am investigating the root cause of a "DNS issue" we had while rebuilding a domain controller and looking for what the actual chain of events is for DNS when you promote a new domain controller. Does anyone know what steps DNS goes through or what triggers steps to happen/wait? (I haven't been able to find that specific information yet)
We have a number of theories for why some clients were not able to resolve a DNS name that didn't change during the 40 minutes it took to demote the old DC (2008) and promote the new one (2008 R2), but all of them come down to timing, and if the server was responding while it was being promoted to being a domain controller.
Going through event logs the DCpromo process was started around 9:54pm and at 10:03:32 DNS server service started, 10:03:40 shows it received a bad DNS packet, then at 10:10:28 it says the ADDS startup was complete, and 10:10:38 it says it is a Domain Controller. Why did DNS log a bad packet before it fully became a domain controller, and why was it even responding if it didn't have the zone fully loaded?
Is there a way to know if it was responding badly to DNS requests during the time it was being promoted to be a domain controller?
at 10:16 when it reported the background loading of all zones was complete all of our issues immediately went away.
I'm trying to figure out why some of our systems didn't go to their secondary DNS server and others did. Some of the clients that had issues were set up through DHCP the same as some that gracefully went to the secondary DNS server.