2 primary domain servers. How to make them know one another without going to a top level domain or root ?

[Kevin Darcy]

=?UNKNOWN?Q?Jo=E3o?= Carlos Roseta Matos wrote:

> I have the following problem:
>
> One company has 2 registered domains, aaa.com and bbb.com.
> Each domain has it's own primary and secondary servers.
> How can I make each primary know the other one, whitout going to the
> top level domain or root ?
>
> I know that if I make one backup of the other and viceversa it would
> work. But there should be an easier ( less network traffic ) solution.

The short answer is that, in addition to becoming a slave -- which is
what I assume you mean by "mak[ing] one backup of the other" -- you could
also try stub zones or selective forwarding. These may or may not result
in less network traffic, depending on a number of factors; size of zone,
frequency of update, refresh and TTL settings, query frequency/variety,
etc.

But unless this is purely a performance issue, I'd question why you don't
just let the nameservers go to the roots and resolve queries in these
domains "naturally". Not *every* query in the domains will go to the root
servers; the referral information will be cached and used accordingly, so
contact with the root servers should be relatively rare.

Are these nameservers perhaps on an internal network where there is no
internal root, i.e. all of the nameservers forward by default towards the
Internet? That'd be a shame. Your situation, i.e. multiple  internal
domains, sounds like a good fit for an internal root setup, and there is
a patch to be hopefully adopted shortly which allow internal roots to
co-exist with default forwarding. And with an internal root, things are
much scalable, if you should ever want to add a third domain, a fourth
domain and so on.

By the way, if you do have default forwarding configured and decide to go
with stub zones, then you'll need to add a "forwarders {}" statement to
the top-level zone of each domain to turn off default forwarding for it.
You also need to do this with slave zones, if there are subzones you wish
to access and you don't care to define forward/slave/stubs individually
for each one.


- Kevin