Going dual-stack, how do apps behave and what to do as an operator (Was: Apple Airport Extreme IPv6 problems?)

Mark Andrews Mark_Andrews at isc.org
Fri Sep 21 11:11:41 UTC 2007

In article <2d106eb50709202254q6f4ea4b7v6beda6deee5f7143 at mail.gmail.com> you write:
>On 9/15/07, Jeroen Massar <jeroen at unfix.org> wrote:
>> [spam: Check http://www.sixxs.net/misc/toys/ for an IPv6 Toy Gallery :)]
>> Somewhat long, hopefully useful content follows...
>> Barrett Lyon wrote:
>> [..]
>[ clip ]
>> Of course when there is only a A or AAAA only that protocol will be
>> used. All applications are supposed to use getaddrinfo() which sorts
>> these addresses per the above specification, the app should then
>> connect() to them in order, fail/timeout and try the next one till it
>Since when is a timeout on the Internet ok?  Haven't we moved beyond

	You mean to say you get 100% connectivity with IPv4?

> This is a controllable timeout. We don't have to do it, which is
> the point. What's the right way to do this?
> Thank you, and thank you Barret for starting the thread. :-)

	I've been running dual stacked for 5 years with a trans
	pacific tunnel to HE (10 hops).  While there have been the
	occasional glitch I don't see much difference between IPv4
	and IPv6.

	Work has also been running dual stacked.  I very rarely fall
	back to IPv4, and given my usage patterns I do notice when
	IPv6 connectivity fails.

	Looping through the addresses as returned by getaddrinfo is
	a reasonable strategy.


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