NS records for subzone cause BIND 9 failures

Kurt Boyack kboyack at gmail.com
Tue Mar 22 03:46:30 UTC 2005

> >When a parent zone has subzone data in it, NS records for the subzone
> >will cause BIND 9 servers to fail to resolve any of the subzone's
> >data. The problem does not exist with 8.2.3, but does with 9.2.1 and
> >9.3.0.
> >
> Well, it's not a "problem"; it's the way DNS is supposed to work. When
> you delegate a zone to other nameservers, then those nameservers own the
> data in the zone, not you. The only exceptions are so-called "glue"
> records describing the nameservers for the child zone. Ordinary records,
> like A records which are not associated with nameservers, MX records and
> so forth, belong to the "closest enclosing zone", i.e. the child (or
> "child-most") zone.

In our situation, the BIND 9 servers are secondary for the parent
zone, but not the subzone. The users at our location cannot resolve
any of the subzone data that is in the parent zone, but users at other
locations where they are running BIND 8 or Microsoft DNS can resolve
it. The subzone data in the parent zone are two NS records and A
records for the two subzone name servers.

It looks like Microsoft DNS will use the data in the parent zone to
query the subzone name servers for the subzone data, but BIND will
not. This is the second time I have run into this problem, and have
solved it by slaving the subzone.

This leaves me with two questions. My original question was why can't
BIND 9 resolve subzone data from a parent zone when NS records for the
subzone are in it?

In other words, if you have a bar.com zone with the following in it:

$ORIGIN bar.com
foo     NS     ns1.foo
$ORIGIN foo.bar.com
ns1    A

Why can you resolve both the A and NS records with BIND 8, but nothing
with BIND 9? If the NS records are removed, the A records will resolve
with BIND 9.

And the other question is can you delegate a subzone by putting NS and
A records for the subzone's servers in the parent zone? The answer
about glue records seems to indicate this is possible and it appears
that Microsoft DNS supports this, but it does not work with BIND 8 or
9. I know Microsoft likes to make their own rules and seem to try to
be incompatible so they can take over the world, but a lot of the
people in other parts of my company are pro Microsoft and would like
to see BIND go away. The perspective "problem" with my BIND 9 servers
is giving them reason to push for a pure Microsoft solution.

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