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Re: [Add] Draft Posting: CNAME Discovery of Local DoH Resolvers

John Levine <johnl@taugh.com> Fri, 26 June 2020 01:24 UTC

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From: John Levine <johnl@taugh.com>
To: add@ietf.org
Cc: ekr@rtfm.com
In-Reply-To: <CABcZeBPTkWeB40wpTowKvEJ-gXA3AL2e-BE+C_FC7Js7-D0DZQ@mail.gmail.com>
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Subject: Re: [Add] Draft Posting: CNAME Discovery of Local DoH Resolvers
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In article <CABcZeBPTkWeB40wpTowKvEJ-gXA3AL2e-BE+C_FC7Js7-D0DZQ@mail.gmail.com> you write:
>I have just posted draft-rescorla-doh-cdisco-00, which describes a
>CNAME-based mechanism for discovering when a local resolver supports
>DoH/TRR. ...

It looks like you're mixing together two questions: "I want an index
into my local DoH table" and "where's a DoH resolver?" They're both
plausible questions but I wouldn't mix them together.

For the first question, a CNAME lookup to doh-resolver.arpa (a name we
can easily ensure never exists in the public DNS) seems OK.

For the second question, I'd do a URI lookup of _doh._tcp.doh-resolver.arpa
or if you don't trust your local crudware resolver to handle URI, a TXT record.

In both cases you can't use DNSSEC but that seems inevitable for this
kind of bootstrap.

R's,
John

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