On killing IPv6 transition mechanisms

Tore Anderson tore.anderson at redpill-linpro.com
Tue Mar 16 16:50:56 CET 2010

* Pete French

> I have a number of them here (the 6to4 is being provided by FreeBSD,
> not an airport, but all the clients are OSX). What would you like me
> to test ?
> BTW, I belive there is some kind of issue with how OSX resolves
> names with bot an A and an AAAA record. I have a feeling that it
> makes two requests, but only uses the one which comes back first or
> something along those lines... Certainly I use Ipv6 on OSx all the
> time for my work, and one of the annoyances is that an IPv6-only
> website which was previously accessible can suddenly vanish as far as
> Safari is concered. Quitting the app and disabling-the-reenabling
> wifi makes it appear again.

Basically to go to dualstacked destinations (www.ripe.net and
www.ipv6.org are especially nice as they'll echo your source address
back to you) and see if it'll connect by using IPv6/6to4 or IPv4.  Or if
it changes depending on which DNS response comes back first as you say,
you should be able to determine that by tcpdumping your port 53/udp traffic.

Also it would be interesting to hear if you're using the latest version
of everything, especially if there's differences in behaviour between

If you're able to break 6to4 on purpose (e.g. dropping all proto-41
packets on the FreeBSD box), how does that change your browsing
experience?  Does dualstacked sites appear to be down or sluggish?

You wouldn't happen to know what's the best way to get in touch with an
Apple software engineer about this issue?  Sigh..  here I thought I saw
the end of the tunnel now that Opera have finally fixed their browser..

Thank you for your help!

Best regards
Tore Anderson
Redpill Linpro AS - http://www.redpill-linpro.com/
Tel: +47 21 54 41 27

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