A question about using forwarders.

[Kevin Darcy]

No, an NXDOMAIN response is considered definitive, and no other 
nameserver/resolver/forwarder will be consulted. The purpose of having 
multiple forwarders is for redundancy in case one or more forwarders 
stop responding or respond too slowly, *not* to get a "second opinion" 
just because you don't like the first answer received. It's basically 
the same methodology that a stub resolver (e.g. a typical PC client) 
uses; in fact, forwarding basically turns your named instance into a 
stub resolver with caching.

As for your larger issue of trying to resolve disparate sets of DNS 
information (e.g. internal and external) within the same namespace 
hierarchy, either break things up into separate zones/subzones, or 
duplicate one set of information into the other zone, e.g. make your 
internal DNS a superset of your external DNS.

- Kevin

Lee Fu-yuan wrote:

>Hi everyone,
>
>I have a question about the usage of the forwarder options.
>Consider a simple setting: 
>	
>	options {
>		....
>		....
>		forwarders {IP_ADDRESS1; IP_ADDRESS2;};
>		....
>	};
>
>Is it possbile that we can ask the DNS server to query the 
>second forwarder with IP_ADDRESS2 if the first forwarder 
>answers our query with NXDOMAIN message? 
>
>
>Similarly, if none of the forwarders have the answer, i.e.,
>they all answers NXDOMAIN, can we let the DNS server perform 
>interative query from root DNS servers?
>
>Thanks a lot.
>
>With best regards,
>
>
>  
>