On Fri, 14 Mar 2008, Rémi Denis-Courmont wrote:
Le Friday 14 March 2008 00:27:26 Pekka Savola, vous avez écrit :
This issue was first reported about 5 years ago by Alain Durand et al and
yet there is no fix yet (and no mention in the default address selection
problem statement), see section 2 of:
http://tools.ietf.org/html/draft-ietf-v6ops-v6onbydefault-03
The main problem is destination address selection rule 2 which requires
that source and destination address scopes must match (which in the case of
v4 private and global addresses is not a very useful comparison given the
prevalence of NAT).
Indeed. And this was (inconclusively) discussed at the mike during the last
v6ops meeting. I had also asked about this a few months ago. Nobody seemed to
care (winter vacation?):
http://www.ops.ietf.org/lists/v6ops/v6ops.2007/msg01150.html
Maybe we need a more systematic approach to deal with RFC3484 issues (as
in, a numbered list of all the problems noted) instead of doing a nice new
features to have PPT slideshow every IETF meeting.
I think we need to "simplify" RFC3484 section 3.2 through removing the IPv4
site-local scope there: we'd be left with only global scope (public addresses
+ RFC1918) and link-local scope (169.254.0.0/16).
I suspect some implementors (at least Windows) already ignore §3.2 for the
sake of reliability. I know Linux does implement ?3.2 to the letter of the
RFC unfortunately. And I have seen people _remove_ AAAA from their server's
DNS records because of this issue, combined with deficient 6to4 relays.
Another problem involves incomplete implementation of RFC3484: some stacks
apply RFC3484 for IPv6, in connect() and sendto() socket APIs, but fail to do
RFC3484 in getaddrinfo(), and simply assume IPv6 is first, and IPv4 second. I
suspect this applies to OSX and BSDs, and also "embedded" C run-times.
Not exactly. The opensource BSD implementations has "proper" RFC 3484 -
they are treating RFC1918 addresses as global scope.
http://www.ops.ietf.org/lists/v6ops/v6ops.2007/msg01151.html
Unfortunately OSX does not have any RFC 3484 implementation.... I reported
few months ago to Apple this issue.....
Best Regards,
Janos Mohacsi
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