Currently we have 2 networks for our the majority of our servers which are not joined for security purposes. Since several servers have multiple interfaces, I’m wondering if I create a different DNS server for each network, how will DNS requests be handled if the interface on one server was to go down. For example a server1 has IPs 10.0.0.1 and 172.16.0.1 and server2 has 10.0.0.2 and 172.16.0.2. If server 1 loses 10.0.0.1, will a hostname request from server2 (e.g. ping server1) always result in a successful connection on the 172.16.x.x network or is it possible it will get the 10.0.0.1 lookup and timeout?
Likewise, if 1 of the DNS servers is on both networks, is it necessary to have 2 DNS servers or is there a way to ensure that the DNS server always returns a valid entry for whatever network the client is querying from (instead of just having 2 A records and DNS doing round-robin, returning the bad entry 50% of the time)?