At Fri, 14 Mar 2008 00:27:26 +0200 (EET),
Pekka Savola <[EMAIL PROTECTED]> wrote:
> While the default router "persistence" is an interesting observation, the
> more
> interesting one is why the default address selection algorithm pick
> source,destination pair of v6:{link-local,global} which is almost certain not
> to work instead of v4:{site-local,global}
> (ietf-464nat is using private addresses).
I think the case of v6:{link-local (only),global} vs
v4:{site-local,global} is special and is not that harmful as long as
the network is properly configured (I know we cannot always assume
that, though). When a link-local address is the only available
address for host, there should normally be no IPv6 default router
either. And if an application tries to both the IPv6 and IPv4 pairs
(which I believe is the case for today's many dual-stack apps) and the
attempt with the IPv6 pair immediately fails (which should also be the
case for TCP communications on many protocol stacks, especially for
those that deprecate the "on-link by default" rule), the application
immediately falls back to the v4 pair and the user won't even be aware
of that.
Again, I'm not necessarily arguing this is negligible, but IMO we
should separate the case where the problem can be avoided by proper
operation from the case where it's impossible or very hard. In that
sense, I think the more problematic case is (as others have already
pointed out) v6:{ULA,global} vs v4:{site-local(RFC1918),global}.
---
JINMEI, Tatuya
Internet Systems Consortium, Inc.
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