How to forward particular names to specific DNS servers?

[Kevin Darcy]

blueprism at my-deja.com wrote:

> Hello,
>
> Is it possible to configure BIND 9 to forward domain name requests
> to a particular DNS server based on the domain name?  For example,
> suppose I want to send all names starting with the letters
> "MYCOMPANY" to a particular DNS server?  A more general case: can
> BIND be configured to support regular expressions within zone files
> in order to push matching requests to particular DNS servers?
>
> I realize this is probably not possible, but if you know of a
> different way to get the same result, a reply would be much appreciated.

This is not possible using full regular expressions, but in BIND 8 at
least, you can forward selectively based on domain. So, for instance, you
can forward everything which ends in "bar.com" to a particular server, but
this wouldn't apply to, say, "www.foobar.com", since foobar.com is a
different domain from bar.com. Last I looked, though, per-domain forwarding
was not yet implemented in BIND 9. Note also that forwarding is always
recursive, so if you're forwarding to a nameserver that isn't authoritative
for the entire tree that you're forwarding, and doesn't honor recursion,
you may get back a possibly-useless referral for some names in that domain.

Other options would include stub or slave zones, but in that case you'd
have to slave/stub *every* zone in the domain tree that didn't have usable
delegations from its parent.


- Kevin