Re: [DNSOP] BCP on rrset ordering for round-robin? Also head's up on bind 9.12 bug (sorting rrsets by default)

神明達哉 <jinmei@wide.ad.jp> Tue, 19 June 2018 18:51 UTC

Return-Path: <jinmei.tatuya@gmail.com>
X-Original-To: dnsop@ietfa.amsl.com
Delivered-To: dnsop@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 5A6D8130DC2 for <dnsop@ietfa.amsl.com>; Tue, 19 Jun 2018 11:51:35 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -0.422
X-Spam-Level:
X-Spam-Status: No, score=-0.422 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, FREEMAIL_FORGED_FROMDOMAIN=0.249, FREEMAIL_FROM=0.001, FROM_EXCESS_BASE64=0.979, HEADER_FROM_DIFFERENT_DOMAINS=0.249, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=no autolearn_force=no
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 WYX7cYoqEuC1 for <dnsop@ietfa.amsl.com>; Tue, 19 Jun 2018 11:51:34 -0700 (PDT)
Received: from mail-lf0-f51.google.com (mail-lf0-f51.google.com [209.85.215.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id CC442130E13 for <dnsop@ietf.org>; Tue, 19 Jun 2018 11:51:33 -0700 (PDT)
Received: by mail-lf0-f51.google.com with SMTP id i15-v6so1088502lfc.2 for <dnsop@ietf.org>; Tue, 19 Jun 2018 11:51:33 -0700 (PDT)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=MYCZMiOgUfh5oJKSh47X+lXCgVm3HGqqAzDADEvS29s=; b=C+6avYZJ3SrXFsYJNkKpRWxY42dSdkSH+6sayHb9ohy2wSbijyahROobNObIslHwzR mhXGQ3euwLTMLGHIiXCxDth3QfzJHmUG9b8tuzy9mykzVriwB3Ke39QdwJQ9xSoEnPJv +iPDvVZFUYXl2sWRu9xGRF6kjQViwrpPLSCR+R7kiMJl/9ZOP/vnkGj7y6ep6ZD3EPpX uNpOnb9DWSmCKwyCEJkMxvgkOflQ4hp1+7g+2/cBMFLRGm/Pbjoa5a0g1AxuYhbhSbqL w/zMaLUT4XT2m2lfcsb+i7L0AbUtL1yxv+k0XioIs8d5lw+eend5pfYpasQ3Ez7WsBN3 fk+w==
X-Gm-Message-State: APt69E0v2UhxNS4vI2jgz4ZUTLaKFUW6IiW4ZjFKw61iQhexNICUykIF 9mrauEcsrAz3ux8x2wXnEyZMrFOti+dVM8BNst8=
X-Google-Smtp-Source: ADUXVKK9gpMllXQSTtlyZnpSku198RqqSqfzGnjgkdxrKTw/4nI79jnPeJFjXC5qeUli5CelgVluUIoCliVHQaLKlTs=
X-Received: by 2002:a2e:5f8f:: with SMTP id x15-v6mr11572047lje.70.1529434291864; Tue, 19 Jun 2018 11:51:31 -0700 (PDT)
MIME-Version: 1.0
References: <CAKC-DJimMOtNCSE95kRs6Dy3dC_mxB=8O2WVA7badp8GK2ci-Q@mail.gmail.com> <20180615171231.GF1126@mx4.yitter.info> <CAHPuVdWP=DVj52diWYTHKqHBET0hFyUWvACT-VpH20iKzed-ww@mail.gmail.com> <CA+nkc8AS6+cZfi_NGT2T+FeQkQ5fKn--HQOOuusL1cYFkdKbKA@mail.gmail.com> <20180615195232.GA5926@jurassic> <CAKC-DJhRJwg7cw8iexCgq9axgjyjnQQaXP2+wD4u=sk3PtypRg@mail.gmail.com> <20180618150157.GB9377@mx4.yitter.info> <5B27EFB7.1020400@redbarn.org> <874lhzu7ae.fsf@mid.deneb.enyo.de> <CAHPuVdXiM3X3hyN14+JJEXWhSrjdepj1PwRDW07mzHmgLcHjAw@mail.gmail.com>
In-Reply-To: <CAHPuVdXiM3X3hyN14+JJEXWhSrjdepj1PwRDW07mzHmgLcHjAw@mail.gmail.com>
From: =?UTF-8?B?56We5piO6YGU5ZOJ?= <jinmei@wide.ad.jp>
Date: Tue, 19 Jun 2018 11:51:18 -0700
Message-ID: <CAJE_bqfjGwMGLTEMp6L77RUihC9Jzkq_BcBVp=643H0RcjnkAQ@mail.gmail.com>
To: Shumon Huque <shuque@gmail.com>
Cc: Florian Weimer <fw@deneb.enyo.de>, dnsop <dnsop@ietf.org>, Paul Vixie <paul@redbarn.org>
Content-Type: text/plain; charset="UTF-8"
Archived-At: <https://mailarchive.ietf.org/arch/msg/dnsop/eN05XYxFvrSzENLV80aOmpyghNU>
Subject: Re: [DNSOP] BCP on rrset ordering for round-robin? Also head's up on bind 9.12 bug (sorting rrsets by default)
X-BeenThere: dnsop@ietf.org
X-Mailman-Version: 2.1.26
Precedence: list
List-Id: IETF DNSOP WG mailing list <dnsop.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/dnsop>, <mailto:dnsop-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/dnsop/>
List-Post: <mailto:dnsop@ietf.org>
List-Help: <mailto:dnsop-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/dnsop>, <mailto:dnsop-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 19 Jun 2018 18:51:36 -0000

At Mon, 18 Jun 2018 17:51:26 -0400,
Shumon Huque <shuque@gmail.com> wrote:

> Client applications delegate address sorting to name resolution functions
> like getaddrinfo() - correct?
>
> Doing some quick tests of getaddrinfo() just now on a recent *NIX machine,
> it appears to return addresses sorted roughly in accordance with RFC
> 6724, but rule 9 (longest prefix match) seems to be only applied to
> IPv6 addresses. For IPv4 addresses (using an upstream resolver
> that randomizes the response RRset), the order returned by getaddrinfo()
> is ever changing - I assume presented in the order received.

The very original implementation of BSD getaddrinfo() conformed to the
RFC, but FreeBSD seems to have changed the behavior a few years ago so
rule 9 wouldn't apply to IPv4 addresses:
https://github.com/freebsd/freebsd/commit/1390d13ae69089142f6c6465dbb24438f295edee
The commit log suggests the rrset round-robin was exactly the
motivation for the change (whether it was good or bad).

--
JINMEI, Tatuya