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Re: [dnsext] BADVER/FORMERR

Mark Andrews <marka@isc.org> Sat, 12 November 2011 08:49 UTC

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To: Ray Bellis <Ray.Bellis@nominet.org.uk>
From: Mark Andrews <marka@isc.org>
References: <20111111025007.B689B17061FA@drugs.dv.isc.org> <8B7F972437853B40865000D86857B1D118DC4B13@wds-exc1.okna.nominet.org.uk>
In-reply-to: Your message of "Fri, 11 Nov 2011 12:42:24 -0000." <8B7F972437853B40865000D86857B1D118DC4B13@wds-exc1.okna.nominet.org.uk>
Date: Sat, 12 Nov 2011 19:49:28 +1100
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Cc: "dnsext@ietf.org" <dnsext@ietf.org>
Subject: Re: [dnsext] BADVER/FORMERR
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In message <8B7F972437853B40865000D86857B1D118DC4B13@wds-exc1.okna.nominet.org.uk>, Ray Bellis writes:
> >  EDNS version processing is supposed to take precedence
> > over examining the query section
> 
> Defined where?  I don't see anything like that in RFC 2308.

EDNS is RFC 2671.  If you don't support the EDNS version in the
request you must send back BADVER.  At that point trying to process
the question section, whatever it is, is moot as the RCODE has
already been set.

> > as the EDNS version can influence the interpretion of the
> > question section.
> 
> Ditto.
> 
> Just out of interest, are there any _existing_ legitimate circumstances where
> QDCOUNT != 1 ?

Seeing if a server is alive.
Getting the EDNS UDP size prior to sending a UPDATE. 
Getting the EDNS version prior to anything.

If I set qcount=2 with ./in/a and ./in/aaaa and edns=50 the correct
rcode for a edns=0 server is BADVER.

-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka@isc.org

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