Your wish goes against established operation and good practice.
All configured DNS servers are supposed to return same results to any query. Hence when multiple servers are configured, then DNS client (resolver) is free to use any of them with no particular affinity. Most use one server for all queries until it fails to respond [*] after which another server is used for all subsequent queries until that one fails. Etc.
[*] Failing to respond is exactly this: server doesn't answer to query. Negative answer doesn't count as failure to respond ans thus not a reason for client to query another server.
So: if one needs two DNS servers which can return answers to queries which are not globally available (e.g. LAN hosts), then one has to host two (or more) separate DNS servers on LAN (one being master for LAN zones, the rest being slaves but still authoritative) and configure the rest of LAN to use those servers.
All configured DNS servers are supposed to return same results to any query. Hence when multiple servers are configured, then DNS client (resolver) is free to use any of them with no particular affinity. Most use one server for all queries until it fails to respond [*] after which another server is used for all subsequent queries until that one fails. Etc.
[*] Failing to respond is exactly this: server doesn't answer to query. Negative answer doesn't count as failure to respond ans thus not a reason for client to query another server.
So: if one needs two DNS servers which can return answers to queries which are not globally available (e.g. LAN hosts), then one has to host two (or more) separate DNS servers on LAN (one being master for LAN zones, the rest being slaves but still authoritative) and configure the rest of LAN to use those servers.
Statistics: Posted by mkx — Mon Mar 25, 2024 7:43 pm