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

From: "Michel Py" <[email-masked]>
Date: Mon, 5 Nov 2001 20:29:01 -0800

Dan -

>> 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.''

Because of two reasons:

1. The same reason as "why do people climb mountains".
- Because it's there.

2. Because in 5 or 10 years, people that have had early exposure to IPv6
and know half of the issues still unknown as of today will make twice as
much as people that don't and will lead the development of the "next
generation Internet" or whatever you want to call it.

Ask that very question again in 10 years?

Michel.

---

From: "D. J. Bernstein" <[email-masked]>
Date: 6 Nov 2001 05:38:31 -0000

I'm asking why I ``SHOULD configure both A and AAAA records.'' This
seems like a complete waste of time. Is it useful? If so, how? If this
massive renumbering is necessary for the IPv6 transition---which it
isn't, according to the published transition plans---then why is it only
for MX servers, and why isn't it a MUST?

> 1. The same reason as "why do people climb mountains".

That's a dumb answer.

> generation Internet" or whatever you want to call it.

That's even dumber.

Hint for the clueless: The reason that there's a potential market for
IPv6 is that IPv6 addresses are intrinsically less expensive than IPv4
addresses. If, however, IPv6 addresses are less _useful_ than IPv4
addresses---because, for example, they won't talk to most of the
Internet unless millions of sysadmins ``climb mountains''---then people
will stick to mechanisms that work, such as web proxies and NAT.

---Dan

---

From: "Jeroen Massar" <[email-masked]>
Date: Tue, 6 Nov 2001 11:48:26 +0100

D. J. Bernstein <[email-masked]> wrote:

> I'm asking why I ``SHOULD configure both A and AAAA records.''
A    : provides access for/to IPv4 and IPv6 aware hosts
AAAA : provides access for/to IPv6 hosts

But.... the big but.. you _cannot_ specify an address like
3ffe:8114:2000:240:290:27ff:fe24:c19f into an A.
IPv6 hosts _can_ communicate with IPv4 hosts with the ::ffff:<ipv4>
compatibility addresses only because
somewhere in between there is a dualstacked machine (actually some kind
of nat between IPv6 and IPv4).
Check http://research.microsoft.com/msripv6/napt.htm for that...

The fact is that an IPv4 only host can never connect to an IPv6 only
node (as it simply doesn't know about IPv6 addressing).

> This seems like a complete waste of time. Is it useful? If so, how? If
this
> for MX servers, and why isn't it a MUST?
the MUST part comes from the: someday there will be IPv6 only hosts
which are MX and aren't IPv4 enabled thus from ones
IPv4 only host you will not be able to contact that part of the
IPv6-internet.

Simple.

Doesn't work:
IPv4-only ----> IPv6-only

Works:
IPv6 -> IPv6
IPv6 -> IPv4 (with the help of napt and/or a dualstacked router
somewhere)

Oh... there is way to access IPv6-only from IPv4-only nodes... use a
Socks server which is on a dualstacked box...
Then let the Socks server (version 5, as v4 doesn't do dns and specifies
IPv4 IP's in it's packets) do the resolving of the hostname and
relay/tunnel/translate the connection onto an IPv6 host where
possible...

Greets,
 Jeroen

PS: If you wanted a seamless IPv4 -> IPv? transition you should have
voted for ascii-nullterminated IP addresses a lot of years ago, but that
would also have solved the IP-address-'full'ness of today and make a
major beating to many routers...

---

From: "Jim Fleming" <[email-masked]>
Date: Tue, 6 Nov 2001 07:44:10 -0600

From: "Jeroen Massar" [email-masked]
"...you should have voted for...a lot of years ago..."

The marketplace will now vote....

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

---

From: "D. J. Bernstein" <[email-masked]>
Date: 6 Nov 2001 16:21:06 -0000

Jeroen Massar writes:
> from ones IPv4 only host you will not be able to contact that part of
> the IPv6-internet.

Irrelevant. A requirement to obtain IPv6 software is not a requirement
to obtain an IPv6 address.

---Dan

---

From: "Jeroen Massar" <[email-masked]>
Date: Tue, 6 Nov 2001 21:10:25 +0100

> to obtain an IPv6 address.

Ehmmm maybe there is, no... let me rephrase that... there is something
missing in this context...

Software (Applications AND stack) that are meant to only support IPv4
have HARDCODED (due to compilation) 32bits addresses.
Software (Applications AND stack) that are meant to only support IPv6
have HARDCODED (due to compilation) 128bits addresses.

So you really do need to have IPv6 support in your software... thus IPv4
_cannot_ no way communicate with an IPv6 only host.

And isn't it so that without software the stack is useless? So software
should be able to use it.

Or am I really missing some precious cluepoints from your point of view?
If so please enlighten me :)

Greets,
 Jeroen