View option implementation

Kevin Darcy kcd at daimlerchrysler.com
Fri Jul 13 19:33:48 UTC 2001


BIND 9 implemented something called "view", but it's not what you see in
_DNS_and_BIND_, Third Edition. It's just a way of presenting different
versions of a zone or set of zones to different clients. With BIND 9
"view"s, you don't need to run multiple nameserver instances to implement
"split DNS".

If you want to do forwarding for Internet names, and at the same time host
multiple internal domains, you could define the apex of every internal
domain as a type slave or stub (except on the master(s), of course),
specifying "forwarders { }" in the zone definition to cancel forwarding for
the entire domain. E.g. if you have "example1.com" and
"example2.com" hierarchies, with some number of subzones under each one,
you'd only need two "zone" definitions ("example1.com" and
"example2.com") in order to cancel forwarding for both hierarchies.
"Stub" is more lightweight than slave in terms of zone-transfer overhead,
but doesn't offer as much redundancy, and depending on various factors
(e.g. size of zone, frequency of change, refresh/TTL settings, query
patterns, whether or not you're using IXFR, etc.) can actually use more
bandwidth and/or perform worse. It is also possible to configure the apexes
as "type forward", in which case you'd specify your actual forwarders
instead of "{ }", but of course forwarding should be avoided if possible
(presumably you have no choice but to forward to resolve Internet names).
Usually stub zones are the best fit here, unless you need the redundancy
that slaving provides.


- Kevin

Laurent Zannettacci wrote:

> Hi there,
> I read a very interesting article about the View option in the DNS &
> BIND book from O Reilly. This option could allow an organization to have
>
> its own internal root for internal resolutions but in keeping the way,
> for internal hosts, to resolve internet hosts names through forwarders.
> Someone could tell me if such kind of option has been implemented and,
> if yes, in which version ?





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