Re: Last Call: <draft-ietf-dhc-option-guidelines-14.txt> (Guidelines for Creating New DHCPv6 Options) to Best Current Practice

Ted Lemon <> Wed, 09 October 2013 15:48 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id AA1AD11E819A; Wed, 9 Oct 2013 08:48:07 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -106.581
X-Spam-Status: No, score=-106.581 tagged_above=-999 required=5 tests=[AWL=0.018, BAYES_00=-2.599, RCVD_IN_DNSWL_MED=-4, USER_IN_WHITELIST=-100]
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id UWDjX2-zqf07; Wed, 9 Oct 2013 08:48:01 -0700 (PDT)
Received: from ( []) by (Postfix) with ESMTP id ACDF611E81BF; Wed, 9 Oct 2013 08:47:54 -0700 (PDT)
Received: from ([]) (using TLSv1) by ([]) with SMTP ID; Wed, 09 Oct 2013 08:47:54 PDT
Received: from ( []) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "*", Issuer "Go Daddy Secure Certification Authority" (verified OK)) by (Postfix) with ESMTP id F2B231B82E5; Wed, 9 Oct 2013 08:47:52 -0700 (PDT)
Received: from ( []) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "", Issuer "Go Daddy Secure Certification Authority" (verified OK)) by (Postfix) with ESMTPS id EA09A190061; Wed, 9 Oct 2013 08:47:52 -0700 (PDT) (envelope-from
Received: from [] ( by CAS-01.WIN.NOMINUM.COM ( with Microsoft SMTP Server (TLS) id; Wed, 9 Oct 2013 08:47:52 -0700
Content-Type: text/plain; charset="windows-1252"
MIME-Version: 1.0 (Mac OS X Mail 7.0 \(1812\))
Subject: Re: Last Call: <draft-ietf-dhc-option-guidelines-14.txt> (Guidelines for Creating New DHCPv6 Options) to Best Current Practice
From: Ted Lemon <>
In-Reply-To: <>
Date: Wed, 09 Oct 2013 11:47:51 -0400
Content-Transfer-Encoding: quoted-printable
Message-ID: <>
References: <> <> <> <>
To: "Cullen Jennings (fluffy)" <>
X-Mailer: Apple Mail (2.1812)
X-Originating-IP: []
Cc: "" <>, "" <>
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: IETF-Discussion <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Wed, 09 Oct 2013 15:48:07 -0000

On Oct 9, 2013, at 11:26 AM, Cullen Jennings (fluffy) <> wrote:
> Help educate me on this a bit - I don't see all the things that get requested of DHCP. What are some examples of things where people are request FQDN where IP would be better. I think having some real examples that have come up would make it easier to see what advice is needed.

DNS server IP address.   NTP server IP address.   Router IP address (not in DHCPv6, of course).   AFTR IP address.   Basically, network infrastructure IP addresses.

Bear in mind that the set of services configured by DHCP ought to be pretty small—just things that really are local network infrastructure services, not things that are specific to the host and not to the network.   It's not even clear to me that NTP ought to be configured by DHCP, and indeed in most cases it is not, despite there being an RFC describing how to do it.

Considering the case of SIP, when you configure SIP I think that's probably a configuration that shouldn't change as the phone moves from network to network.   So it shouldn't be configured by DHCP.   In the case where the phone happens not to be likely to move from network to network, you could _get away_ with using DHCP.   But a solution that would work for phones that _do_ move from network to network would also work for phones that do not, and that solution would therefore be preferable, particularly as an MTI solution, since it addresses all use cases.

As I mentioned in the IESG discussion, it is a shame that aggsrv didn't become a working group, since it was intended to address this specific problem, at least as I understood it.