Yesterday's Windows update causes IPv4 to be default

Dan Wing dwing at
Thu Nov 15 17:55:02 CET 2012

> -----Original Message-----
> From: at [mailto:ipv6-
> at] On Behalf Of Lorenzo
> Colitti
> Sent: Thursday, November 15, 2012 4:08 AM
> To: Nick Hilliard
> Cc: Erik Kline; Mike Jones; IPv6 Ops list
> Subject: Re: Yesterday's Windows update causes IPv4 to be default
> On Wed, Nov 14, 2012 at 4:42 PM, Nick Hilliard <nick at> wrote:
> 	I respect Apple's position on HE much more - at least they did
> their
> 	homework and made a smart technical decision instead of
> implementing a very
> 	naive algorithm with clear drawbacks like this.
> The Apple algorithm has drawbacks too. To wit:
> 1. It biases in favour of IPv4 by trying the A record first.
> 2. By always preferring the fastest protocol, even on a perfect dual-
> stack network it will use IPv6 only ~50% of the time (unless IPv4 is
> degraded).
> 3. It imposes twice the connection load on server operators.

Not forever, though; the web browser will re-connect to the same
address next time.  And Apple's algorithm does learn if IPv6 or
IPv4 are faster, on a per destination subnet basis.  The problem 
is mostly when IPv6 and IPv4 are the same speed, it learns they
are the same speed and keeps gathering statistics on IPv4.  That
can certainly be improved, and I would bet a fine Thanksgiving 
dinner that it is being improved.

> 4. It's non-deterministic, which some websites don't like as they tie
> your cookies to your IP address.


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