Microsoft's participation in World IPv6 day

Iljitsch van Beijnum iljitsch at
Wed Jun 8 05:59:24 UTC 2011

On 8 jun 2011, at 7:42, Christopher Palmer wrote:

> I'm not an ISP - but I absolutely expect that IPv6 roll-outs have long time-horizons and are fairly complex. So I hope folks are looking at IPv6 NOW, and not simply waiting for Google/Bing/Yahoo/Interwebz to enable permanent content access and organizational justification.

You have to remember that the content guys need few addresses and once they have them they rarely need more, and IPv6 or not is pretty much a binary thing: yes for everyone, no for everyone. It's the opposite for consumer ISPs: they need tons of addresses on an ongoing basis but they can (for instance) give IPv6 to new users while not changing anything for existing users. So once some hurdles such as the limited availability of IPv6-capable CPEs and a plan on how to provision IPv6 are taken the ISPs have a lot of incentive to roll out IPv6 while the content guys can conceivably stay on IPv4 for a long time. The fact that IPv6 client to IPv4 server is an easy problem but the other way around a very hard one also points in this direction.

BTW, how are you guys dealing with path MTU discovery for IPv6? I've seen a few sites that have problems with this, such as, but you guys seem ok.

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