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Hello, the 6to4/IPv4 preference problem I've posted about a few times earlier appears to be solved in the OS X 10.6.5 previews. I'd like to send a big «thank you» to everyone in Apple involved in making that happen! However, there's still some rough edges and in sending this message I'm hoping there's a chance they too will get included in the final release of 10.6.5. First, the Teredo prefix (2001:0::/32) is still preferred above IPv6. Teredo provides inferior, last-resort type connectivity (much like 6to4), so it should be de-preferred in the same way as 6to4 is. Second, if OS X has a default route but no globally scoped IPv6 address (e.g. after receving a RA with no prefix information), Firefox seems to break towards dual-stack sites. Using tcpdump I can see that only Firefox solicits AAAA records in this situation, while Safari and Chrome appears to optimise them away - perhaps by supplying ai_family=AF_INET when calling getaddrinfo(). This problem has been been observed in the wild by Heise who recently went dual-stack, see: <http://www.heise.de/newsticker/meldung/IPv6-Tag-bei-heise-de-Erste-Ergebnisse-1081201.html>. This situation also broke Safari in OS X 10.6.4, while Chrome handled in well in both 10.6.4 and 10.6.5. I also did some brief testing on the bug about OS X ignoring AAAA responses if they arrive later than the A responses. From what I can tell, there's a timeout of about 125ms before OS X gives up waiting for AAAA responses. So if a user's DNS resolver has only the A record cached, OS X might end up preferring IPv4 in situations where IPv6 would normally be preferred. The opposite is not true, however. OS X 10.6.5 did not start to prefer IPv6 in situations where IPv4 would normally be preferred (e.g. when using 6to4) before I delayed the A responses by 25 seconds. I do not know if this behaviour is the exact same as in 10.6.4 or not, though. Best regards, -- Tore Anderson Redpill Linpro AS - http://www.redpill-linpro.com/ Tel: +47 21 54 41 27 _______________________________________________ Do not post admin requests to the list. They will be ignored. Ipv6-dev mailing list (email@hidden) Help/Unsubscribe/Update your Subscription: This email sent to email@hidden
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