nanog mailing list archives

Re: swedish dns zone enumerator


From: Stephane Bortzmeyer <bortzmeyer () nic fr>
Date: Thu, 2 Nov 2023 10:25:22 +0100

On Thu, Nov 02, 2023 at 04:09:24PM +1100,
 Mark Andrews <marka () isc org> wrote 
 a message of 90 lines which said:

I also see QNAME minimisation in action as the QTYPE is NS.  This
could just be a open recursive servers using QNAME minimisation.
With QNAME minimisation working correctly all parent zones should
see is NS queries with the occasional DNSKEY and DS query.  Both
BIND and Knot use NS queries for QNAME minimisation.

I disagree. NS queries were used in the first RFC about QNAME
minimisation (which was experimental) but the current one (which is on
the standards track) now recommends A or AAAA queries
<https://www.rfc-editor.org/info/rfc9156>, specially section 2.1.

Other query types and/or prefixes do not work as they have
undesirable side effects.

Rather the contrary, some broken firewalls in front of authoritative
name servers were crashing when using NS queries. Hence the choice of
address queries. (Also, it improves privacy since it makes more
difficult to see you are doing QNAME minimisation.)

I would not like anyone to take seeing mostly NS queries as any
evidence of bad practice.

We agree here.


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