Yesterday's Windows update causes IPv4 to be default

[Dan Wing]

> -----Original Message-----
> From: Sander Steffann [mailto:sander at steffann.nl]
> Sent: Thursday, November 15, 2012 1:49 AM
> To: Dan Wing
> Cc: 'Mike Jones'; 'Tassos Chatzithomaoglou'; ipv6-ops at lists.cluenet.de
> Subject: Re: Yesterday's Windows update causes IPv4 to be default
> 
> Hi,
> 
> > The URL it tries to visit is http://ipv6.msftncsi.com/ncsi.txt, and
> > searching the Internet for that FQDN yields some details of how it
> > works.  If it can't retrieve the expected text at that URL, Windows
> > will order IPv6 to the bottom of its address preference table (by
> > tweaking its internal RFC3484 rules).  The success (or failure) to get
> > to that IPv6 site is remembered for that network for 30 days, and then
> > re-tested.  I don't know how to encourage it to try a fresh test, but
> > there must be a registry setting to force that to occur.
> 
> 
> WTF? So one failure (either locally or of a Microsoft webserver) causes
> an IPv6 outage of one month... It will be 'interesting' to see internet
> traffic patterns shift for a month when ipv6.msftncsi.com has an
> outage...

The stability of ipv6.msftncsi.com is quite good now.  I know of several
probes checking it frequently, from different locations.

> I think this is a *very* bad design decision.
> Sander

-d