[dns-operations] resolv.conf and resolving IPv6-only domains/NSes

[Frank Bulk]

Holger:

The Debian box is not IPv6 only.  

I had presumed (incorrectly) that I could list a bunch of DNS servers (IPv4
and IPv6-only) in resolv.conf and the IP stack would handle SERVFAIL
gracefully and move on to the next one.  Apparently that's not the case,
which is why your recommendation that all the servers listed in resolv.conf
be dual-stack is a good idea.

Frank

-----Original Message-----
From: Zuleger, Holger, VF-DE [mailto:holger.zuleger at vodafone.com] 
Sent: Wednesday, November 03, 2010 12:26 PM
To: frnkblk at iname.com; Stephane Bortzmeyer
Cc: dns-operations at dns-oarc.net
Subject: RE: [dns-operations] resolv.conf and resolving IPv6-only
domains/NSes

> Stephane:
> 
> You are correct, whether my tool requests resolution via IPv4 
> or IPv6 for
> onlyv6.com shouldn't matter as long as the queried resolver has IPv6
> connectivity.
> 
> So what I've learned is that if I want to resolve query 
> v6-only domains,
> such as onlyv6.com, I had better make sure that the first DNS 
> server in my
> resolv.conf has IPv6 connectivity.  Even better, make sure 
> all of them do.

No.
If your client is ipv6-only then it doesn't make sense to
use an IPv4 resolver.
Additionally each of the ipv6 resolvers in your list *must* be
dual-stack, or need the help of an dual stack resolver (e.g. via
BINDs dual-stack-server command).

If the domain is a v6-only domain, at least the authoritative name
servers of
the domain have to be dual stack.

Regards
 Holger