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Re: [dns-privacy] Trying to understand DNS resolver 'discovery'

Stephane Bortzmeyer <bortzmeyer@nic.fr> Wed, 27 November 2019 14:28 UTC

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Date: Wed, 27 Nov 2019 15:28:42 +0100
From: Stephane Bortzmeyer <bortzmeyer@nic.fr>
To: "Konda, Tirumaleswar Reddy" <TirumaleswarReddy_Konda@McAfee.com>
Cc: Stephane Bortzmeyer <bortzmeyer@nic.fr>, Phillip Hallam-Baker <phill@hallambaker.com>, "dns-privacy@ietf.org" <dns-privacy@ietf.org>
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Subject: Re: [dns-privacy] Trying to understand DNS resolver 'discovery'
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On Wed, Nov 27, 2019 at 09:07:15AM +0000,
 Konda, Tirumaleswar Reddy <TirumaleswarReddy_Konda@McAfee.com> wrote 
 a message of 72 lines which said:

> > *All* "automatic discovery of the DoH resolver" schemes are broken
> > by design and I really wonder why people keep suggesting them.
> 
> Not all discovery mechanisms have security holes, you may want to
> look into
> https://tools.ietf.org/html/draft-reddy-dprive-bootstrap-dns-server-05.

It seems to me that this draft has exactly the same problem as every
other "resolver discovery" proposal: it gives complete power to the
access network to indicate the resolver to use. If you use DoH/DoT, it
is because you don't trust the access network. Relying on it to
indicate a DoH/DoT resolver is pointless.

For instance, if your access provider has a lying resolver and you
want to escape it with DoH/DoT access to an external resolver, I don't
see how this draft helps you.

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