I think I understand that in DNS a given zone must return its own nameservers (as NS records) in order that intermediary DNS servers are able to then query information directly about that domain.
However, looking at the configuration file in Microsoft DNS, I see:
; ; Zone NS records ; @ NS ns1.mydomain.com. ns1.mydomain.com. A x.x.x.x @ NS ns2.mydomain.com. ns2.mydomain.com. A x.x.x.x
My question is, why are there A records added for the nameservers? Does this mean that if I change the IP address of my nameserver, I need to ensure that every domain pointing at that nameserver is updated with the new IP address?
Or are these A records updated automatically by the DNS software upon a change?