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Re: [DNSOP] RFC 1035 vs. mandatory NS at apex?

Tony Finch <dot@dotat.at> Thu, 07 February 2019 14:16 UTC

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Date: Thu, 7 Feb 2019 14:16:02 +0000
From: Tony Finch <dot@dotat.at>
To: Ted Lemon <mellon@fugue.com>
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Subject: Re: [DNSOP] RFC 1035 vs. mandatory NS at apex?
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Ted Lemon <mellon@fugue.com> wrote:
> On Feb 7, 2019, at 7:44 AM, Petr Špaček <petr.spacek@nic.cz> wrote:
> > When looking at it from resolver perspective, what is the resolver
> > supposed to do with query "zone. NS" if there is no authoritative NS set
> > in the zone? Return NOERROR+NODATA?
>
> It should reply with no error and no data.  But this is okay, because
> you never need to ask this question in order to resolve a name.  If you
> are looking up an NS record with intent to use it, it’s going to be in
> the parent zone, where you are looking for a delegation.

But in this scenario things soon go wrong, because RFC 2181 says the
NODATA reply replaces the delegation records in the resolver's cache. This
means that if a client explicitly asks for the NS records of a zone that
lacks them, resolution for other records in the zone will subsequently
fail.

Tony.
-- 
f.anthony.n.finch  <dot@dotat.at>  http://dotat.at/
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