Re: [Doh] [Ext] DoH client-server interoperability vs. strict HTTP parameter checking

Paul Hoffman <paul.hoffman@icann.org> Sat, 01 June 2019 14:42 UTC

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From: Paul Hoffman <paul.hoffman@icann.org>
To: Christoph <cm@appliedprivacy.net>
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Thread-Topic: [Ext] [Doh] DoH client-server interoperability vs. strict HTTP parameter checking
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Date: Sat, 1 Jun 2019 14:42:41 +0000
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Subject: Re: [Doh] [Ext] DoH client-server interoperability vs. strict HTTP parameter checking
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On Jun 1, 2019, at 5:36 AM, Christoph <cm@appliedprivacy.net>; wrote:
> Should DoH servers reject requests with a '400 Bad Request'
> response when the request contains HTTP parameters not defined in RFC8484

No.

> or
> should DoH servers be less strict and simply ignore additional HTTP
> parameters and proceed with processing the relevant HTTP parameters
> required to provide an answer?

Yes.

RFC 8484 makes it clear that a "DoH server" is just an HTTP server that understands the DoH semantics. Trying to limit it beyond that is just wrong (or maybe just lazy).

--Paul Hoffman