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

Patrick McManus <> Sun, 24 March 2019 21:05 UTC

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From: Patrick McManus <>
Date: Sun, 24 Mar 2019 22:04:04 +0100
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To: Patrick McManus <>
Cc: "Winfield, Alister" <>, "" <>, Eric Rescorla <>, "" <>, "" <>, "" <>, "" <>, "" <>
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Subject: Re: [DNSOP] [Doh] [EXTERNAL] Re: New I-D: draft-reid-doh-operator
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I want to add one thought to the general argument that goes along the lines
of "I need to enforce a policy on my network, and doh will just encourage
more https interception - we have gotten nowhere."

This argument assumes a scenario where the network is trusted by the
application and can require/achieve host or application configuration.
Indeed - deploying trust anchors to these clients is the only way you're
going to intercept https as the notion of network defined configuration of
"trusted proxies" and the like is consistently rejected by clients. That
seems like the right standard for DNS as well - go ahead and configure a
different policy but do it via an existing authenticated configuration
mechanism like you would use for adding a trust root.

However, rather than adding a root I would suggest that if you're doing
client configuration for network-local DNS policy, that you deploy a DoH
server that enforces that policy and point DoH clients at it through the
various enterprise config mechanisms. It doesn't require any kind of access
that adding a trust root does not. This has the desirable property that the
application can reliably know what server is providing DNS service in a
fully authenticated way. Perhaps in a "my way or the highway" scenario it
will choose the highway. That's fair enough - that should be a real
choice.  When you just intercept an informed decision cannot be

Use of non-default trust roots is also a property generally visible to
applications. Most allow it as a matter of user configuration.