Secondary queried?

[Kevin Darcy]

Exactly how are you using the terms "primary", "secondary" and "client"?

A "stub resolver" (which is how most PC-class devices are configured)
will typically work through a statically-configured (sometimes
DHCP-supplied) list of nameservers until it gets some sort of answer. It
doesn't know or care whether the answer comes from the "primary" or
"secondary" nameserver for the zone, or even (as it usually does) from a
nameserver which isn't even authoritative for the zone.

On the other hand, a *full* resolver will try all nameservers for a
particular zone before it gives up on a query. Again, it doesn't know or
care whether the nameserver it queries for a zone is "primary" or
"secondary", but it *does* care whether the answer is marked as
authoritative or not (if a delegated nameserver answers with
non-authoritative responses, this is the condition known as "lame").

Finally, you brought up the topic of forwarding. Forwarding overrides the
normal algorithm that a full resolver uses to obtain information about a
zone. Sure, you could point your "forwarders" at both a "primary" and a
"secondary" nameserver for a particular zone, in that order, but why
bother? If you don't forward at all, and the "primary" nameserver is
unavailable, your nameserver will get around to asking that
"secondary" nameserver anyway, assuming that it is actually a
*published* nameserver for the zone (as opposed to being what is called a
"stealth slave"). So forwarding doesn't really buy you anything here. All
it does is force your queries to go the "primary" nameserver, assuming
it's available, which may not be the optimal path. Far better to let
named figure out the "best" nameserver instead of forcing it to always
use a particular one.


- Kevin


Smithz wrote:

> In the case that the primary name server is available but does not
> have the zone configured will the client making the request make an
> additional request to the secondary name server as it could possibly
> have a valid zone file still available the ability to resolve the
> request?
>
> If the answer is NO would it be acceptable to include the secondary in
> the list of forwarders giving the primary the ability to ask the
> secondary during the time the secondary has the correct information?
>
> Thanks in advance!
>
> Ed