Re: [Doh] [Ext] a tad confused on response sizes

Tony Finch <dot@dotat.at> Tue, 05 June 2018 14:17 UTC

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Date: Tue, 5 Jun 2018 15:17:26 +0100
From: Tony Finch <dot@dotat.at>
To: Paul Hoffman <paul.hoffman@icann.org>
cc: bert hubert <bert.hubert@powerdns.com>, "doh@ietf.org" <doh@ietf.org>
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Subject: Re: [Doh] [Ext] a tad confused on response sizes
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Paul Hoffman <paul.hoffman@icann.org>; wrote:
> On Jun 5, 2018, at 5:05 AM, bert hubert <bert.hubert@powerdns.com>; wrote:
> >
> > 	A DNS API server is allowed to answer queries with any valid DNS
> > 	response.  For example, a valid DNS response might have the TC
> > 	(truncation) bit set in the DNS header to indicate that the server
> > 	was not able to retrieve a full answer for the query but is
> > 	providing the best answer it could get.  A DNS API server can reply
> > 	to queries with an HTTP error for queries that it cannot fulfill.
> > 	In this same example, a DNS API server could use an HTTP error
> > 	instead of a non- error response that has the TC bit set.
> >
> > This seems says sending a TC response is some kind of error
>
> Not at all. The first sentence is quite explicit.

Thinking about this further, I think this is a bug, because a DoH client
doesn't have any way to recover from TC.

Tony.
-- 
f.anthony.n.finch  <dot@dotat.at>;  http://dotat.at/
Shannon, Rockall, Malin: Variable or cyclonic, 3 or 4. Slight, occasionally
moderate. Mainly fair. Moderate or good.