IETF Logo Mail Archive

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

Andrew Sullivan <ajs@anvilwalrusden.com> Tue, 05 June 2018 22:24 UTC

Return-Path: <ajs@anvilwalrusden.com>
X-Original-To: doh@ietfa.amsl.com
Delivered-To: doh@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 1262F130DF9 for <doh@ietfa.amsl.com>; Tue, 5 Jun 2018 15:24:22 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.9
X-Spam-Level:
X-Spam-Status: No, score=-1.9 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=yitter.info header.b=ca5bAWiu; dkim=pass (1024-bit key) header.d=yitter.info header.b=W5AX0mVf
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id W_suYSmVti26 for <doh@ietfa.amsl.com>; Tue, 5 Jun 2018 15:24:20 -0700 (PDT)
Received: from mx4.yitter.info (mx4.yitter.info [159.203.56.111]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 4D90B130DE2 for <doh@ietf.org>; Tue, 5 Jun 2018 15:24:20 -0700 (PDT)
Received: from localhost (localhost [127.0.0.1]) by mx4.yitter.info (Postfix) with ESMTP id 247E0BDEF9 for <doh@ietf.org>; Tue, 5 Jun 2018 22:24:19 +0000 (UTC)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yitter.info; s=default; t=1528237459; bh=aJe9m1im4goKs8PTTCPhoZGNoq316ZiqapED564zqKU=; h=Date:From:To:Subject:References:In-Reply-To:From; b=ca5bAWiu9OZZi+3JzBGHz8mGyJDgoa8psEJ3gtlbZGP2Tcg7XnU9EV1C4gD7T6ZIN fOLfbHNamuj7/YnL3c7tu/FIvM1txqS0gfqMFz8rRuvUXMSJ67O7NqaX2c8tdEPGBk eFA0HXuoeEEsArubdWRqAwZiMG7SnvEyG+NWGezk=
X-Virus-Scanned: Debian amavisd-new at crankycanuck.ca
Received: from mx4.yitter.info ([127.0.0.1]) by localhost (mx4.yitter.info [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id HPpCbMIwU0bJ for <doh@ietf.org>; Tue, 5 Jun 2018 22:24:17 +0000 (UTC)
Date: Tue, 05 Jun 2018 18:24:16 -0400
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yitter.info; s=default; t=1528237457; bh=aJe9m1im4goKs8PTTCPhoZGNoq316ZiqapED564zqKU=; h=Date:From:To:Subject:References:In-Reply-To:From; b=W5AX0mVfk17BAMLQrQsAy9o8VvFyB9NB0/cI9qS90B25vB4nmc8qKXR8kWK46BU7C 929GvdjKKqWqEuCZ0dDWHwX0zfbChajuzGgLk56tVcGGp3iSPj6SqvsiQuRvjMy8xp kPM4hqXrRbXWKAQRzRhWtMEcndyEDuNrcYmwxBAs=
From: Andrew Sullivan <ajs@anvilwalrusden.com>
To: doh@ietf.org
Message-ID: <20180605222416.GZ3011@mx4.yitter.info>
References: <alpine.DEB.2.11.1806051604150.1809@grey.csi.cam.ac.uk> <20180605152355.6tlbeqvt7luklwjl@nic.fr> <alpine.DEB.2.11.1806051710290.1809@grey.csi.cam.ac.uk> <BYAPR19MB22489BE90FE768BCB13BD40B94660@BYAPR19MB2248.namprd19.prod.outlook.com> <alpine.DEB.2.11.1806051759430.1809@grey.csi.cam.ac.uk> <BYAPR19MB2248B0ADD763FF82E8C6C2E194660@BYAPR19MB2248.namprd19.prod.outlook.com> <alpine.DEB.2.11.1806051908040.1809@grey.csi.cam.ac.uk> <BYAPR19MB22489076D7E7A6780F78CCF094660@BYAPR19MB2248.namprd19.prod.outlook.com> <alpine.DEB.2.11.1806052125170.1809@grey.csi.cam.ac.uk> <8CB4E291-95D8-4AC2-9CBA-84D54A6E93DA@icann.org>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <8CB4E291-95D8-4AC2-9CBA-84D54A6E93DA@icann.org>
Archived-At: <https://mailarchive.ietf.org/arch/msg/doh/GzTWzEQtbRlL2_MR3BdlypNo97M>
Subject: Re: [Doh] [Ext] a tad confused on response sizes
X-BeenThere: doh@ietf.org
X-Mailman-Version: 2.1.26
Precedence: list
List-Id: DNS Over HTTPS <doh.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/doh>, <mailto:doh-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/doh/>
List-Post: <mailto:doh@ietf.org>
List-Help: <mailto:doh-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/doh>, <mailto:doh-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 05 Jun 2018 22:24:23 -0000

On Tue, Jun 05, 2018 at 10:10:33PM +0000, Paul Hoffman wrote: 
> Resolver 1 sends a query to a Resolver 2 (who allows forwarding) over TCP. Resolver 2 asks an authoritative,  gets a response with TC bit set on, tries on TCP, and gets a failure on TCP. Resolver 2 should send the partial answer it got over UDP to Resolver 1. That answer to Resolver 1 should have the TC bit set on, or not, depending on what you think that RFC 1035 "implies".
> 

Alternatively, maybe Resolver 2 should send some error (I'm guessing
SERVFAIL is the answer, though I suppose Vixie would be unhappy with
that guess).

The problem, of course, is that a TC'd answer is literally telling you
it's incomplete, and in principle you have an incomplete RRset, which
is maybe important.  It's not clear you should use it, and it's pretty
clear (at least to me) that you shouldn't cache it.

A

-- 
Andrew Sullivan
ajs@anvilwalrusden.com

v2.23.0 | Report a Bug | By Email