Subject: Re: (ngtrans) Re: ipv6-smtp-requirement comments?

From: "D. J. Bernstein" <[email-masked]>
Date: 5 Nov 2001 04:43:36 -0000

[email-masked] writes:
> benefit is, you can make use of both IPv4 and IPv6 for email delivery.

I already have an IPv4 address that everyone uses for mail delivery. How
exactly do I benefit from taking the time to maintain two addresses for
a single computer?

> still, there are IPv6-capable servers out there.

I don't see what relevance that has to my question.

---Dan

---

From: "Jim Fleming" <[email-masked]>
Date: Mon, 5 Nov 2001 13:32:49 -0600

----- Original Message ----- 
From: "D. J. Bernstein" <[email-masked]>

> exactly do I benefit from taking the time to maintain two addresses for

Some people want to move away from the monopoly control
of the IPv4 ".ARPA Community"....

It all boils down to fairness.

Which list do you think is more fair ?
The "toy" IPv4 Internet Early Experimentation Allocations ?
http://www.iana.org/assignments/ipv4-address-space
or
The Proof-of-Concept IPv8 Allocations ?
http://www.ntia.doc.gov/ntiahome/domainname/130dftmail/unir.txt

Why would people pay for Address Space, when it is FREE ?

Jim Fleming
http://www.DOT-BIZ.com
http://www.in-addr.info
3:219 INFO

---

From: Keith Moore <[email-masked]>
Date: Mon, 05 Nov 2001 17:43:53 -0500

> exactly do I benefit from taking the time to maintain two addresses for

you can then receive mail from folks who have only IPv6 access.

whether, and/or when, you think this is worth your trouble is a separate 
question.

Keith

---

From: "Jeroen Massar" <[email-masked]>
Date: Tue, 6 Nov 2001 01:55:55 +0100

D. J. Bernstein <[email-masked]> wrote:
> exactly do I benefit from taking the time to maintain two addresses
for a single computer?

I sincerely hope you got a steady uplink and machine, or have at least a
secondary MX defined as a backup...
(or you should be able to bring your connection up in like <4 days ;)

And if you read the document properly you would have read that it is for
the transistion period between IPv4 to IPv6... thus allowing you to
communicate with both the IPv4 world AND the IPv6 world at the same time
while the IPv4 world still exists and the IPv6 world is starting to
fill...
Also note that when we come into the IPv6-only world form you can return
back to your single IP address for a single computer ;)
Actually as IPv4 != IPv6 it's not another IP address as that would be
like comparing chickens with frogs or something... (even though both are
protocols/animals)

> I don't see what relevance that has to my question.
Hopes that answers your question completely as you did cut out an awfull
lot...

Greets,
 Jeroen

---

From: "D. J. Bernstein" <[email-masked]>
Date: 5 Nov 2001 23:51:28 -0000

> you can then receive mail from folks who have only IPv6 access.

I thought the plan was to allow IPv6 hosts to send packets to existing
IPv4 addresses. People who already have IPv4 addresses can simply
upgrade to IPv6-aware software. Isn't this the whole point of
IPv4-compatible IPv6 addresses? 

You seem to be saying that this isn't the plan. You seem to be saying
that the plan is to deploy IPv6 hosts that can't reach the IPv4
universe. This means that everyone MUST acquire and deploy an IPv6
address for every server.

In neither situation is it sensible to say ``If a site has ... dual
stack reachability, the site SHOULD configure both A and AAAA records
onto its MX hosts.'' This SHOULD is unnecessary in the first situation
and ludicrously insufficient in the second situation.

---Dan

---

From: "Jim Fleming" <[email-masked]>
Date: Mon, 5 Nov 2001 19:32:40 -0600

----- Original Message -----
From: "D. J. Bernstein" <[email-masked]>
To: <[email-masked]>
Sent: Monday, November 05, 2001 5:51 PM
Subject: Re: (ngtrans) Re: ipv6-smtp-requirement comments?

> > > exactly do I benefit from taking the time to maintain two addresses
for
> IPv4 addresses.
-------------------------

"the plan"

It is ironic that people live in a world where there they claim there
is "ONE true root" (their root) and when it comes to TLDs, it is their
way or the highway....yet, these same people seem to have MANY
IPv4 to IPv6 transition plans, none of which seem to work....

"ICANN represents that it has no authority to implement new TLDs"
http://www.icann.org/tlds/correspondence/esi-v-icann-13nov00.htm

Jim Fleming
http://www.IPv8.info
IPv16....One Better !!

---

From: [email-masked]
Date: Tue, 06 Nov 2001 11:54:08 +0900

>IPv4-compatible IPv6 addresses? 

	No.  IPv4-compatible address (like ::10.1.1.1) is designed to
	let two IPv4/v6 dual stack nodes communicate with each other
	with IPv6, over IPv4 clouds.  It is supposed to be used when,
	between two IPv4/v6 dual stack nodes, IPv4 connectivity is available
	and IPv6 connectivity is unavailable.

IPv4/v6 dual stack node A
   |
   | IPv6 packet encapsulated into IPv4 packet
   |
IPv4/v6 dual stack node B

itojun

---

From: "D. J. Bernstein" <[email-masked]>
Date: 6 Nov 2001 04:15:49 -0000

[email-masked] writes:
> with IPv6, over IPv4 clouds.

RFC 2893 explains how hosts without IPv4 addresses can communicate with
hosts without IPv6 addresses. RFC 2893 observes that compatibility with
the existing IPv4 universe is essential for the success of IPv6.

In other words: According to the published transition plan, my existing
IPv4 addresses will allow me to talk to hosts on IPv6 addresses, if I
have IPv6 software.

So why should I bother to acquire and maintain IPv6 addresses for my
machines? Even if I do have access to IPv6 address space, why should I
go to even the slightest effort to make use of it? So far I haven't seen
even a shred of justification for this ``SHOULD.''

---Dan

---

From: [email-masked]
Date: Tue, 06 Nov 2001 13:21:36 +0900

>the existing IPv4 universe is essential for the success of IPv6.

	no.  I guess you read sections on "IPv4 compatible address" incorrectly.

itojun

---

From: "Jim Fleming" <[email-masked]>
Date: Mon, 5 Nov 2001 22:44:04 -0600

----- Original Message ----- 
> machines?

For each person or company, the answer may be different. In some
cases, people may be insulated from the various Adress Space Management
"regimes", and never have to deal with the issues directly. In other words,
they get IP blocks free from their University or employer and assume that
the blocks arrive from the sky, with no cost tied to them.

In some cases, companies may have a "killer ap" or a new system which
may grow to have a population that can not afford to pay $25,000 per
year for a block of IP addresses. Now, such a company may be hard to
imagine, but I bet if one tries, they could consider some possibilities.

http://www.xbox.com/Odyssey/

San Francisco
Pier 30/32 Embarcadero
Nov. 1st - Nov. 4th 

Los Angeles
Santa Monica Pier
Nov. 8th - Nov. 10th 
<<<<<<<<<<<<<<<<<<ICANN Meeting...
San Diego
San Diego Sports Arena
Nov. 15th - Nov. 17th 

Phoenix
Mill Ave Fall Fest
Nov. 30th - Dec. 2nd 
----

Jim Fleming
http://www.IPv8.info
IPv16....One Better !!

---

From: "D. J. Bernstein" <[email-masked]>
Date: 6 Nov 2001 05:02:00 -0000

> no.  I guess you read sections on "IPv4 compatible address" incorrectly.

RFC 2893, in sections 4 and 5, explains in detail how a host with an
IPv4 address can receive IPv6 packets from hosts with IPv6 addresses,
and send IPv6 packets to hosts with IPv6 addresses.

In effect, the entire IPv4 address space is incorporated into the IPv6
address space. Existing IPv4 hosts need IPv6 software, but they don't
need to be assigned new addresses. Once all the software around the
Internet supports IPv6, and the necessary routing infrastructure is in
place, it will be safe to put new machines on IPv6 addresses.

Now, if you don't think that's how the transition is supposed to work,
how do you think it _is_ supposed to work?

---Dan

---

From: "Jim Fleming" <[email-masked]>
Date: Tue, 6 Nov 2001 01:01:16 -0600

----- Original Message -----
> address space.

If you focus on Address Space, separate from the protocol, and you
take the short-term view, there is no need for IPv6. A quick extension to
the existing IPv4 can allow for 15 more Internets to be easily deployed
with no change to the existing routers and computers. All one has to do
is to split the 8-bit TOS field into two 4-bit fields and they could deploy
an entire new 32-bit address space each year, for the next 15 years and
each would be as large as the existing IPv4 Address Space.

The problem with this is that it continues to grant unfair advantages to the
current owners of the IPv4 Address Space, assuming that it would be too
difficult to have each of the 16 planes having a different owner set.
Instead,
there seems to be some part of the population that is willing to move away
from the IPv4 Address Space in order to avoid the high fees, and the
unfair distribution of allocations.

Jim Fleming
http://www.IPv8.info
IPv16....One Better !!

---

From: [email-masked]
Date: Tue, 06 Nov 2001 16:36:08 +0900

>and send IPv6 packets to hosts with IPv6 addresses.

	no, you got it wrong.  section 4 and 5 talks about technique
	used by IPv4/v6 dual stack nodes, to communicate using IPv6
	over IPv4 cloud.  it involves the use of IPv6-over-IPv4 tunnel.

	section 4 talks about the use of preconfigured IPv4 address for the
	outer header (therefore, it can be used by a specific pair of IPv4
	addresses).  the packet will look like this:
		IPv4 header (src = src node's IPv4, dst = dst node's IPv4)
		IPv6 header
		payload

	section 5 talks about automatic tunnelling, which makes it possible
	to dynamically decide the destination IPv4 address.  when IPv6
	destionation address ::x.y.z.u is used, the packet will be encapsulated
	towards IPv4 address x.y.z.u.  the packet will look like this:
		IPv4 header (src = src node's IPv4, dst = x.y.z.u)
		IPv6 header (dst = ::x.y.z.u)
		payload

	in summary, they are for communication using IPv6 between IPv4/v6
	dual stack nodes over IPv4 cloud.  this has nothing to do with
	communication between IPv4-only and IPv6-only nodes.

itojun

---

From: Pekka Savola <[email-masked]>
Date: Tue, 6 Nov 2001 11:37:00 +0200 (EET)

On Tue, 6 Nov 2001 [email-masked] wrote:
[snip]
> 	communication between IPv4-only and IPv6-only nodes.

Itojun,

I think Dan was advocating that dual-stack nodes would _only_ have the 
compatible address, and that way one could avoid the address management 
problem.  You could hardcode (evil!) in the software that if destination 
MX is 1.2.3.4 and you have IPv6, you could send it to ::1.2.3.4.

There are a lot of problems with this approach, including:
 - IPv6 DS nodes would have to have global ipv4 address (!!)
 - All nodes would have to implement automatic tunneling and enable it
 - The mail sender cannot know from MX A record whether the destination 
supports IPv6 unless it's stated by AAAA records.  Should the sender 
always default to IPv4 unless it's IPv6-only -- some might want to 
configure the preference.
 - There actually exist IPv6-only nodes, or nodes where using IPv4 is only
the last resort, which already require (address)  architecture; that is, 
some may actually want to prefer IPv6 architecture that may not depend on 
IPv4.

-- 
Pekka Savola                 "Tell me of difficulties surmounted,
Netcore Oy                   not those you stumble over and fall"
Systems. Networks. Security.  -- Robert Jordan: A Crown of Swords

---

From: "Jim Fleming" <[email-masked]>
Date: Tue, 6 Nov 2001 07:40:10 -0600

There are people who, when asked whether they support IPv6,
respond with:

ping6 ::192.168.0.1
ping6 ::[IPv4 Address]

....and say Yes....and that is about the extent of their interest...
...they do not seem to care whether they are connected to anything...

Jim Fleming
http://www.IPv8.info
IPv16....One Better !!

---

From: Erik Nordmark <[email-masked]>
Date: Tue, 6 Nov 2001 13:49:51 +0100 (CET)

> the existing IPv4 universe is essential for the success of IPv6.

Dan,

What you are describing is impossible in the general case.
In order for an IPv4-only node to be able to communicate with some
other node at the IP layer that other node needs to have an IPv4
address - the IPv4-only node needs to put something into
the destination field in the IPv4 header. 

So RFC 2893 doesn't claim to solve this impossible problem.

There are outlines of possible approaches that were at least outlined in
the now expired  draft-ietf-ngtrans-dstmext1-aiih-00.txt
and draft-ietf-ngtrans-siit-dstm-00.txt.
The idea in those drafts is just to not permanently allocate an
IPv4 address to identify the IPv6-only nodes that are communicating
with IPv4-only nodes, but instead do this only when such communication
is occurring or believed to be about to occur.
For communication from the IPv4-only node this can be accomplished by
deferring the allocation of that IPv4 address until there is
DNS lookup for an A record for the IPv6-only node.

Of course, this approach is subject to DoS attacks by just doing DNS lookups
of A records for IPv6-only nodes, so it isn't clear to me that it
will be that useful.

The alternative is to move the problem up the protocol stack
e.g. by having application layer gateways (http proxies, mail relays, etc)
on dual IPv4/IPv6 boxes and somehow configure things so that the
communication between IPv4-only and IPv6-only nodes go through those
boxes.

   Erik

---

From: "D. J. Bernstein" <[email-masked]>
Date: 6 Nov 2001 16:15:13 -0000

[email-masked] writes:
> IPv4-only

Irrelevant. We are talking about hosts where the software supports IPv6.
(This means every host on the Internet, if IPv6 is going to succeed.)

This document recommends, but does not require, that some, but not all,
of those hosts set up IPv6 addresses even if they have IPv4 addresses.
This makes no sense. The only possible situations are

   * IPv4 addresses will remain reachable from the entire Internet---
     this is the RFC 2893 plan, and the only hope for IPv6 to succeed,
     because it means that people _don't_ need to set up new addresses;
     or

   * IPv4 addresses will become unreachable from part of the Internet---
     this would mean that everyone is required to set up new addresses.

Either way, the document is wrong.

---Dan

---

From: "D. J. Bernstein" <[email-masked]>
Date: 6 Nov 2001 16:25:36 -0000

Erik Nordmark writes:
> an IPv4-only node

Irrelevant. This is getting rather tiresome.

---Dan

---

From: Laurent Toutain <[email-masked]>
Date: Wed, 21 Nov 2001 10:26:06 +0100

A new version of the DSTM draft has been submitted to the draft editor. Until then, 
the draft is avalaible on http://www.rennes.enst-bretagne.fr/~toutain/draft-ietf-ngtrans-dstm-05.txt

Laurent

---

From: Jim Bound <[email-masked]>
Date: Tue, 27 Nov 2001 15:43:45 -0500 (EST)

Folks,

The new draft of dstm-05 is out. We moved the dhcpv6 solution to the
appendix with a static and RPCv6 solution to implement DSTM.  Also we now
have a DSTM implementation running thanks to the engineers at ENST France
and the guidance and leadership of Laurent Toutain.  Laurent also did a
talk and presentation at last weeks Paris IPv6 Deployment Conference, I
will send pointer for that talk to Bob and Tony if its appropriate to
forward.

At this time we would like to move to last call and have the Chairs
support to do so.  So you should see that call to move to RFC Proposed
Standard and Standards track.

As far as DSTM-Extensions.  We want to discuss with some folks offline at
Salt Lake City as there are DOS and implementations issues for that spec.
We will update you as we learn more.

thanks
/jim