I've almost got my head wrapped around NS delegation records.
I have this question though: Can a non-authorative dns server containing a domain zone ever return a record from that zone instead of proceeding to the server in the NS record?
example.com with nameserver =
ns1.A.example has the zone
example.com with the following:
NS = ns1.B.example A = 192.0.2.4
ns1.B.example with the zone
example.com has the following:
NS = ns1.B.example A = 192.0.2.8
192.0.2.8 is the authoritative answer, and both name servers listed above should always return
192.0.2.8 when queried.
Is there ANY situation where
192.0.2.4 would be returned as an answer? Or would that record NEVER be accessed because of the NS record not matching?