Subject: Re: Site local

From: "J. Noel Chiappa" <[email-masked]>
Date: Sat, 23 Nov 2002 23:56:00 -0500

> From: Iljitsch van Beijnum <[email-masked]>

    > there is an interesting development in the IPv6 working group: they
    > reached consensus it is a good idea to look at globally unique,
    > non-routable (although this part was immediately challenged) address
    > space

Hoo, boy, is this a dangerous move in policy terms. You can bet people that
get those addresses will set up a hue and cry about "why can't they be
routable globally"?

    > If large enterprises can use this type of address space for all their
    > internal stuff, renumbering becomes much easier as there are no
    > security issues

I don't know about that - don't you still need globally routable addresses for
all machines that want to talk to the rest of the Internet - which I would
think would be most of them (or is everyone's desktop machine getting to the
Web through an intermediary)?

    > In my opinion, this along with host-multihoming solutions should be
    > enough to lower the need for multihoming by injecting a globally
    > visible /48 into the routing table a good deal.

Well, there's another possibility. This fits nicely with 16+16 type
multihoming (where the inner address is your globally unique "host
identifier", and the outer address is currently the place to send you
packets); the inner address could be from this space.

Of course, you still have to examine all the issues with who adds the second
header, and when and how, and all the security issues. But most of those are
inevitable in *any* scheme which has two separate namespaces...

	Noel

---

From: Iljitsch van Beijnum <[email-masked]>
Date: Sun, 24 Nov 2002 12:54:47 +0100 (CET)

> get those addresses will set up a hue and cry about "why can't they be

I'm afraid you are a bit late in offering odds, as this happened within
seconds.  :-)

> Web through an intermediary)?

I would propose using the site local addresses for everything that is
strictly internal, and using globally routable addresses for everything
else. That way, a site wouldn't have to give its own globally routable
addresses better access than any other globally routable addresses, so
renumbering globally routable addresses no longer has any security
impact.

(This could of course also be done with current site local addresses but
this becomes a big mess when different sites connect together.)

> packets); the inner address could be from this space.

Yes. However, it is important to differentiate between addresses that
are unroutable by design and addresses that are unroutable because of
limitations in the routing system, as this limitation may be lifted at a
later date using exact this type of mechanism. Another question is
whether we need these addresses to have some kind of structure. If we
do, we have to speak up now.

---

From: Brian E Carpenter <[email-masked]>
Date: Mon, 25 Nov 2002 10:04:49 +0100

> I'm afraid you are a bit late in offering odds, as this happened within

You're getting way ahead of the facts here. There's no assurance
that the IPv6 WG will reach consensus on this, no assurance that
the IESG will agree, and no assurance that the IANA will assign
whatever address space is proposed in the end.

> > Web through an intermediary)?

With new application-level mechanisms such as Web Services coming along,
IPv6 with globally routable addresses is just what we need to get away
from the broken firewall/proxy model of security. So I agree with Noel.
We need globals more than ever.

The idea of globally unique locals came up in IPv6 for a different reason-
to allow intermittently connected networks to have stable internal
connectivity *and* to establish VPNs or to merge with other similar
networks. Bogus security arguments were not used.

   Brian