delegation with multiple NS including localhost

[Sylvain Bertrand]

Stephane Bortzmeyer wrote:

> On Thu, Jan 08, 2004 at 11:59:32AM +0100,
>  Sylvain Bertrand <Sylvain.Bertrand at supelec.fr> wrote 
>  a message of 36 lines which said:
> 
> 
>>My /var/named/db.bar.org (on ns.bar.org) would look like this:
>>
>>#------- CUT HERE -------
>>foo          NS          ns.foo.bar.org
>>ns.foo.bar   A           101.102.103.104
>>
>         ^^^^
>         Cut this one




That's right, I should not have typed .bar (assuming I had the proper 
$ORIGIN).

 
> 
>>foo          NS          ns.bar.org
>>#------- CUT HERE -------
>>
>>As you can see, I've delegated foo to both ns.foo.bar.org and 
>>ns.bar.org, which is localhost.
>>
> 
> No problem. ns1.nic.fr, master of ".fr", does delegate gouv.fr to
> itself.
>  
> 
>>I've seen on this ML's archives that bind would choose the fastest of 
>>the two NS records for foo, and forward the request.
>>
> 
> Not *your* BIND. The BIND of a remote site, trying to use
> foo.bar.org. 


Ok I get it. So the client's nameserver chooses the fastest between 
ns.foo.bar.org and ns.bar.org, right?


> If *your* BIND is both the authoritative server for foo.bar.org and a
> cache/forwarder for local clients, it will not even try to find the
> fastest server: it has the data, it replies.

It's authoritative for the bar.org zone, but it's only delegating for 
the requests concerning foo.bar.org. The bind on ns.bar.org has no data 
about the hosts in the zone foo.bar.org.


>>I know it seems a little bit odd to delegate to yourself, 
>>
> 
> Not at all.
> 



Since ns.bar.org has no data for foo.bar.org, isn't it useless to 
delegate to itself?