What do do when you have bind as caching resolver which forwards to your DNS servers which do recursive resolving and host primary and secondary of your local domains and upstream link goes down?
To my surprise, caching server can't resolve your local domains although both primary and secondary of those domains are still available on your network and can resolve your domains without problem (when queried directly).
That's because caching server tries to do recursive resolving using root servers which aren't available if your upstream link is down, so even your local domains aren't available to clients using caching server.
Solution is simple if you know what it is. Simply add your local zones on caching server with type forward:
zone "ffzg.hr" {
type forward;
forwarders {
193.198.212.8;
193.198.213.8;
};
};
zone "ffzg.unizg.hr" {
type forward;
forwarders {
193.198.212.8;
193.198.213.8;
};
};
This will work, since queries for those zones are no longer
recursive queries, so they don't need root servers which aren't
available without upstream link.