Subject: Re: [dhcwg] Re: DHCID and the use of MD5 [Re: Last Call:'Resolution ofFQDN Conflicts among DHCP Clients' to ProposedStandard]

From: Ted Lemon <[email-masked]>
Date: Mon, 28 Nov 2005 21:36:05 -0700

On Monday 28 November 2005 20:00, Hallam-Baker, Phillip wrote:
> OK so why are you proposing a new protocol rather than writing a
> description of the protocols that are already in use?

It's inconvenient to use TXT records, because they are not specific to the 
purpose.   If the user wants TXT records on the name for some *other* purpose 
than marking the name with a DHCID, it doesn't work.

We aren't defining a new protocol - just a new RRtype.   The DNSEXT working 
group passed this through last call.   The only reason we're not yet using it 
is that, well, it's been very slow getting the entire package through last 
call, as witness this current conversation.

I appreciate that you like an opportunity to pontificate about DNSSEC, and am 
duly amused that you saw one here and leapt upon it.   However, those of us 
who have been working on standardizing a method by which DHCP servers may 
interoperate while maintaining DNS records for DHCP clients, for the past 
decade, would appreciate it if you would leave off it in this case.   This 
protocol has absolutely nothing to do with DNSSEC, other than that, like 
DNSSEC, it is related to the DNS.

Thanks.

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From: "Hallam-Baker, Phillip" <[email-masked]>
Date: Mon, 28 Nov 2005 19:00:43 -0800

> From: [email-masked] [mailto:[email-masked]] On 
> Behalf Of Bernie Volz (volz)

> This technique has been in use for years by implementations 
> using TXT records because we've been unable to get the DHCID 
> RR approved.

Correctly prefixed TXT records work just as well as new RRs and are
completely compatible with the deployed infrastructure. If you attempt
to cut new DNS RRs you will hit the problem that your proposal is now
dependent on deployment of a new infrastructure which has no deployment
strategy.

Lets get back to the idea that a standard is a description of running
code. The DNS group has become a bottleneck for deployment of a lot of
technology. This should not be acceptable. There is a fundamental
extensibility flaw in DNS, new RRs must be understood by the sender,
receiver and intermediate infrastructure.

The DNSEXT group appears to believe that their objectives should be to
create as much of an incentive to upgrade to DNSSEC capable
infrastructure as possible and that the way to do this is to gate all
proposed uses of the DNS on cutting a new RR.

This is not a good strategy, DNSSEC is a double ended adoption problem,
the problem is not that the promise of DNSSEC is insufficient incentive
for deployment, the problem is that early adopter deployment of DNSSEC
has negligible incentive.

The Pareto optimal solution here is for the IAB to specify a method of
introducing new features that use the DNS that is entirely compatible
with deployed DNS infrastructure. These in turn create new dependencies
on the DNS that create a near term demand for DNSSEC and an early
adopter incentive. The DNSSEC people get an early adopter market for
their proposal, people looking to extend the DNS can do so without
committing error 33. 

For example one of the discussions in DKIM is on what to do with the
ESTG vehicle set up for early development. The idea that most people
seem to think is a good one is to turn it into a branding vehicle
similar to WiFi. So that just as people advertise that their product is
WiFi compatible to mean 'yes it really works' there would be an ESTG
brand that a registrar could use to say 'yes I do provide the services
necessary to support DKIM signed email'. This then leads naturally to
the question of levels of support, a level 1 registrar might do the bare
minimum necessary to support DKIM (allow the relevant records to be
defined), the requirements for level 2 might well include support for
DNSSEC (at least I would argue that they should require DNSSEC support).

---

From: Mark Andrews <[email-masked]>
Date: Tue, 29 Nov 2005 15:25:49 +1100

> dependent on deployment of a new infrastructure which has no deployment

	Not this old chestnut again.

> receiver and intermediate infrastructure.

	Incorrect.  Only the DHCP elements need to understand this.
	For everything else it should be treated as a opaque blob.

	The intent of RFC 1034/1035 was for new RRs to be treated
	as opaque blobs.  You don't need RDLEN if you don't expect
	to treat unknown as opaque blobs. 

	This was clear to me when I first read those RFC's back in
	the early 90's.

	RFC2535 (March 1999) made it absolutely clear that unknown
	RR's were to be treated as opaque blobs.  It is now 6 years
	later and you are saying we should be worrying about
	implementations that were clearly broken on the first day
	they deployed.

> proposed uses of the DNS on cutting a new RR.

	Hogwash.
 
> has negligible incentive.

	This has absolutely nothing to do with the deployment of
	DNSSEC.

> Ietf mailing list
> [email-masked]
> https://www1.ietf.org/mailman/listinfo/ietf
> 
--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: [email-masked]

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From: Mark Stapp <[email-masked]>
Date: Tue, 29 Nov 2005 09:08:26 -0500

there is one thing buried in here that's worth answering:

>dependent on deployment of a new infrastructure which has no deployment
what we are trying to do is to produce something that allows 
interoperability. that's different from documenting existing 
similar-but-not-quite implementations. there is no "compatible" at this 
time - but we would like to get there.

-- Mark

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From: Sam Hartman <[email-masked]>
Date: Wed, 30 Nov 2005 03:51:13 -0500

>>>>> "Ted" == Ted Lemon <[email-masked]> writes:

    Ted> On Monday 28 November 2005 20:00, Hallam-Baker, Phillip
    Ted> wrote:
    >> OK so why are you proposing a new protocol rather than writing
    >> a description of the protocols that are already in use?

    Ted> It's inconvenient to use TXT records, because they are not
    Ted> specific to the purpose.  If the user wants TXT records on
    Ted> the name for some *other* purpose than marking the name with
    Ted> a DHCID, it doesn't work.

Phil is suggesting something like _dhcid.domain .

--Sam

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From: Ted Lemon <[email-masked]>
Date: Wed, 30 Nov 2005 10:42:48 -0700

> Phil is suggesting something like _dhcid.domain .

This is why it's so important to read the drafts carefully, and in detail, to 
the point where you understand how the protocol works, and only then consider 
proposing changes to it.   Because of the way the protocol uses DNS update 
prerequisites, that can't work.   And the way the protocol uses DNS update 
prerequisites is required to get the functionality that we want.

---

From: "David W. Hankins" <[email-masked]>
Date: Wed, 30 Nov 2005 08:44:05 -0800

> Phil is suggesting something like _dhcid.domain .

Except the difference between NXDOMAIN and NXRRSET is important for the
DHCID.

-- 
David W. Hankins		"If you don't do it right the first time,
Software Engineer			you'll just have to do it again."
Internet Systems Consortium, Inc.		-- Jack T. Hankins