Re: [DNSOP] [Doh] New I-D: draft-reid-doh-operator

Ted Lemon <> Fri, 22 March 2019 11:14 UTC

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From: Ted Lemon <>
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Date: Fri, 22 Mar 2019 07:14:04 -0400
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To: John Levine <>
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Subject: Re: [DNSOP] [Doh] New I-D: draft-reid-doh-operator
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On Mar 21, 2019, at 6:50 PM, John Levine <> wrote:
> I believe that for DoT, the idea is that the client just probes the
> DNS server address on port 853 and uses it if it gets an answer.  I
> suppose you could try the same thing on port 443 but that seems
> riskier.

This is a workaround for the absence of a way that the network can signal that the local resolver speaks DNS-over-TLS.  It would be nice if there were a way to explicitly signal the availability of this functionality, so that the stub resolver didn’t have to probe for it.   I think this is only relevant to DNS-over-TLS, however—I don’t think there’s any reason to use DoH if you trust the local resolver.