Subject: RE: Thoughts on the draft-hinden last call

From: "Christian Huitema" <[email-masked]>
Date: Tue, 4 Nov 2003 09:21:43 -0800

> On Mon, Nov 03, 2003 at 10:45:07PM -0800, Alain Durand wrote:
> >
> > As I explain in a previous message, this last property is not
verified
> > by the hinden/haberman draft, as when those addresses leak,
> > they would create untraceable problems, very similar to the one
> > caused by RFC1918 leaks today.
> 
> But could we ever stop leakage?
> 
> And would it not be more dangerous if hijacked or randomly picked
prefixes
> leaked instead of well-known (probabilistically unique) prefixes?

Let's assume that the need won't go away. We have de facto three local
addressing proposals: use the existing site local prefix, hijack a
prefix in the 2000::/3 space, or draft-hinden. Site administrators who
perceive this need will pick one of these three proposal. How do they
compare from a "leak" point of view? My take is as follow:

- using site local is roughly equivalent to using net 10 in IPv4. The
address range can be filtered in routers, but it is ambiguous. Ambiguity
prevents tracing the source of the leaks.

- hijack a prefix is roughly equivalent to the pre-RFC-1958 situation in
IPv4, e.g. alumni reusing the MIT address space. The address range can
be filtered in some routers, but not in all of them. Leaks are difficult
to even notice, and result in misdirection of traffic to an unsuspecting
party. Leaks in the routing protocols result in routing disruption.

- the addresses proposed in draft-hinden appear to be strictly better
than either the existing site-local or hijacked addresses. They can be
filtered in routers. Attempts at uniqueness give us a reasonable hope of
tracing the source of leaks. They don't conflict with existing
addresses, so the leaks don't affect the connectivity or the traffic
load of third parties.

In short, the proposed addresses cannot eliminate application level
leaks, but they can definitely reduce their consequences, and do a much
better job at that than the alternatives.

-- Christian Huitema  

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From: Tim Chown <[email-masked]>
Date: Tue, 4 Nov 2003 17:25:53 +0000

> better job at that than the alternatives.

I think this is a good summary and a good reason to move forward with the
draft-hinden proposal as a best compromise (since no solution is perfect).

Tim

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From: Hans Kruse <[email-masked]>
Date: Tue, 04 Nov 2003 17:43:38 -0500

Thank you!  I was trying to get to the same point, but your summary is much 
better!

And no, I absolutely do not think we should try and wait for routable PI 
space, which seems to be the only other suggestion made on this list.

> better job at that than the alternatives.

Hans Kruse, Associate Professor
J. Warren McClure School of Communication Systems Management
Adjunct Associate Professor of Electrical Engineering and Computer Science
Ohio University, Athens, OH, 45701
740-593-4891 voice, 740-593-4889 fax

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From: Keith Moore <[email-masked]>
Date: Tue, 4 Nov 2003 18:21:12 -0500

Excellent analysis.  I fully concur.

Keith