Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Extension Field drafts -- Four separate drafts

Miroslav Lichvar <mlichvar@redhat.com> Wed, 28 August 2019 11:26 UTC

Return-Path: <mlichvar@redhat.com>
X-Original-To: ntp@ietfa.amsl.com
Delivered-To: ntp@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 0546F120105 for <ntp@ietfa.amsl.com>; Wed, 28 Aug 2019 04:26:07 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -6.901
X-Spam-Level:
X-Spam-Status: No, score=-6.901 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, SPF_PASS=-0.001] autolearn=ham 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 vbayMcHFMTy5 for <ntp@ietfa.amsl.com>; Wed, 28 Aug 2019 04:26:05 -0700 (PDT)
Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 86D8E120100 for <ntp@ietf.org>; Wed, 28 Aug 2019 04:26:05 -0700 (PDT)
Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4F1FC85545 for <ntp@ietf.org>; Wed, 28 Aug 2019 11:26:05 +0000 (UTC)
Received: from localhost (holly.tpb.lab.eng.brq.redhat.com [10.43.134.11]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C64315D9E2 for <ntp@ietf.org>; Wed, 28 Aug 2019 11:26:04 +0000 (UTC)
Date: Wed, 28 Aug 2019 13:26:01 +0200
From: Miroslav Lichvar <mlichvar@redhat.com>
To: ntp@ietf.org
Message-ID: <20190828112601.GL24761@localhost>
References: <1B4A56E7-16A6-4767-9268-BCF4BEB9A247@isoc.org> <BCA949D7-7D92-43A9-9766-573559A9FC70@meinberg.de> <5D66392D020000A100033273@gwsmtp.uni-regensburg.de> <8F6BAF5F-CC7B-47B9-90FD-BD20D6ABE845@meinberg.de> <20190828103752.GI24761@localhost> <3f4b55ca-02d9-a470-229b-40860866efbf@nwtime.org> <20190828111458.GJ24761@localhost> <e50112dd-f918-1135-74c8-a738ecb70b70@nwtime.org>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <e50112dd-f918-1135-74c8-a738ecb70b70@nwtime.org>
User-Agent: Mutt/1.12.0 (2019-05-25)
X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14
X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Wed, 28 Aug 2019 11:26:05 +0000 (UTC)
Archived-At: <https://mailarchive.ietf.org/arch/msg/ntp/QGV_i21EI67iAXrr9KHGgE2zado>
Subject: Re: [Ntp] Antw: Re: Calls for Adoption -- NTP Extension Field drafts -- Four separate drafts
X-BeenThere: ntp@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: <ntp.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ntp>, <mailto:ntp-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/ntp/>
List-Post: <mailto:ntp@ietf.org>
List-Help: <mailto:ntp-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ntp>, <mailto:ntp-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 28 Aug 2019 11:26:07 -0000

On Wed, Aug 28, 2019 at 04:19:29AM -0700, Harlan Stenn wrote:
> On 8/28/2019 4:14 AM, Miroslav Lichvar wrote:
> > Hopefully with something better than the current refid field based on
> > (hashes of) addresses. Something like your suggested-refid proposal,
> > except the extension field would contain both the ID of the server
> > (randomly generated) and the ID of the its reference.
> 
> Extension fields are optional.

Most clients don't need to know the refid, so to me it makes sense for
the refid information to be optional.

> I'm very curious how the ID if the remote server's reference will be
> useful, and not just another attack vector.

It's a random number and not an address. So it should be better than
the NTPv4 refid, right?

> > This could fit into the space of the NTPv4 refid and reference
> > timestamp, but it would take 64 of those 96 bits and I'm not sure if
> > 32 bits is enough for the other new stuff.
> Exactly what do you see as the use-cases for this information in the
> base packet?  Exactly how would this information be used?

It seems you agree it should be optional.

-- 
Miroslav Lichvar