Re: [Acme] Support for domains with redundant but not immediately synchronized servers

Michael Wyraz <michael@wyraz.de> Tue, 09 February 2016 11:11 UTC

Return-Path: <michael@wyraz.de>
X-Original-To: acme@ietfa.amsl.com
Delivered-To: acme@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 3CF781A8909 for <acme@ietfa.amsl.com>; Tue, 9 Feb 2016 03:11:55 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.55
X-Spam-Level:
X-Spam-Status: No, score=-1.55 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HELO_EQ_DE=0.35, HTML_MESSAGE=0.001, RP_MATCHES_RCVD=-0.001] autolearn=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 KSKVP-ZnkVxd for <acme@ietfa.amsl.com>; Tue, 9 Feb 2016 03:11:53 -0800 (PST)
Received: from mail.wyraz.de (web.wyraz.de [37.120.164.129]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id F0F5E1A8908 for <acme@ietf.org>; Tue, 9 Feb 2016 03:11:52 -0800 (PST)
Received: from localhost (localhost [127.0.0.1]) by mail.wyraz.de (Postfix) with ESMTP id 5B0E1A30A4 for <acme@ietf.org>; Tue, 9 Feb 2016 12:11:49 +0100 (CET)
X-Virus-Scanned: Debian amavisd-new at web.wyraz.de
Received: from mail.wyraz.de ([127.0.0.1]) by localhost (web.wyraz.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id MDqegBuf7y1t for <acme@ietf.org>; Tue, 9 Feb 2016 12:11:48 +0100 (CET)
Received: from [192.168.1.200] (p578521F0.dip0.t-ipconnect.de [87.133.33.240]) (Authenticated sender: michael@wyraz.de) by mail.wyraz.de (Postfix) with ESMTPSA id 7A9E8A30A3 for <acme@ietf.org>; Tue, 9 Feb 2016 12:11:48 +0100 (CET)
From: Michael Wyraz <michael@wyraz.de>
To: acme@ietf.org
References: <565C84A1.9040102@wielicki.name> <20151204084601.GQ18430@eff.org> <255B9BB34FB7D647A506DC292726F6E13BB473EFFB@WSMSG3153V.srv.dir.telstra.com> <56A0C558.2070202@wielicki.name> <046f30469e8d4cdfafb01b7e7f9d4608@usma1ex-dag1mb1.msg.corp.akamai.com> <56B9BDD8.9010008@wielicki.name>
Message-ID: <56B9C974.6000700@wyraz.de>
Date: Tue, 09 Feb 2016 12:11:48 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1
MIME-Version: 1.0
In-Reply-To: <56B9BDD8.9010008@wielicki.name>
Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="PiiDoiVeMOH2BLfpwR4wtHOmo1smdql7P"
Archived-At: <http://mailarchive.ietf.org/arch/msg/acme/YOpNQk0Uppbf0JgCWu9sbDoWJ-c>
Subject: Re: [Acme] Support for domains with redundant but not immediately synchronized servers
X-BeenThere: acme@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: Automated Certificate Management Environment <acme.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/acme>, <mailto:acme-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/acme/>
List-Post: <mailto:acme@ietf.org>
List-Help: <mailto:acme-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/acme>, <mailto:acme-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 09 Feb 2016 11:11:55 -0000

Hello Jonas,

thank you for the proposal. I think addressing such setups is a good idea.

The solution you propose works only if dns round robin is used (i.e. all
the real server ips in A or AAAA). But there are similar setups where
the redundant servers are behind some load balancer where a completely
different ip is used. Another widely used scenario is geo-based dns. In
this case, the Acme server would only see his "nearest" ip address.

IMO a better way to support your scenario as well as those I described
above would be to check for an SRV-Record before checking A-Records.
This would be 100% compatible with existing acme http-01 clients. In
your case you would resolve the SRV record to the machine that has the
acme client running on. The acme-server would check for the SRV-Record
for an address to lookup the challenge's response at. If no SRV record
is specified, it would continue with A and AAAA records.

Kind regards,
Michael.

>
>
> On 21.01.2016 15:13, Salz, Rich wrote:
>
> >> I am not at all familiar with the processes in an IETF WG. What
> >> is the way forward to get my proposal either into the protocol or
> >> officially dismissed?
>
> > This is the way it works. :)  People post to the mailing list and
> > there's discussion.  At some point, the chairs will see if there is
> > consensus to do it.
>
> > So things are working as designed.  It's informal and a bit messy.
>
> > What might help focus discussion is if you made a pull request with
> > your specific wording changes.
>
> I gave it a shot: https://github.com/ietf-wg-acme/acme/pull/82
>
> I will appreciate any feedback on that proposal.
>
> best regards,
> jwi
> > _______________________________________________ > Acme mailing list >
Acme@ietf.org > https://www.ietf.org/mailman/listinfo/acme