How to forward request to another NS?

[Kevin Darcy]

MH wrote:

> I'm trying to learn DNS and currently have two nameservers set up in a lab
> environment (no Internet). Each NS services a separate network. The two
> networks are connected by a router. How do I configure each NS so that
> requests for a client address that exists on the remote network are passed
> to the NS on that network for resolution?

DNS is typically used to map names to addresses. In that capacity, your
requirements seem to make little sense -- by the time a nameserver maps a
given name to an address and realizes that the address is "on the remote
network", it's already done all of the work necessary to *resolve* that name,
and therefore there is no reason to forward the query. It would just answer
the query and be done with it.

Or, are you referring to "reverse DNS", i.e. the address-to-name mapping
function of DNS? In that case, just maintain separate zones on each of the
nameservers for the addresses in their respective networks' ranges, and then
use forwarding/delegation/stubbing so that they can query each other when
necessary, or make them slaves of each other's zones so that they don't have
to send any queries on demand. Note that if your networks don't happen to
cleave nicely on octet boundaries, you may have to employ the technique
described in RFC 2317 (or something like it) in order to pull this off.

> Also, any pointers to information on setting up DDNS would be much
> appreciated.

That's a fairly vague request. From a BIND standpoint, the main things to
bear in mind about DDNS are a) to put an appropriate allow-update clause in
the relevant zone definition(s), and b) forget about using the zonefile of a
Dynamic Update-enabled zone for anything useful (including manual updates),
since named "owns" that file now and writes it whenever and however it feels
like.


- Kevin