Yesterday's Windows update causes IPv4 to be default

[Dan Wing]

> -----Original Message-----
> From: Brian E Carpenter [mailto:brian.e.carpenter at gmail.com]
> Sent: Thursday, November 15, 2012 8:55 AM
> To: Dick Visser
> Cc: Dan Wing; Tassos Chatzithomaoglou; Mike Jones; ipv6-
> ops at lists.cluenet.de
> Subject: Re: Yesterday's Windows update causes IPv4 to be default
> 
> On 15/11/2012 11:09, Dick Visser wrote:
> > On 14 November 2012 23:20, Dan Wing <dwing at cisco.com> wrote:
> >
> >> 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.
> >
> >
> > It looks like there is, see attached regedit screendump.
> 
> Thanks for that. It looks as if one should clear EnableActiveProbing to
> get rid of this feature.

Thanks for tracking that down, Dick.

-d


>     Brian
> 
> > It differs from the one in the superuser.com blog post, in that there
> > are v6 versions of some parameters.
> >>From the looks of it, it allows you to specify which host names,
> > addresses, and web server file paths should be used for the probe.
> > So while the defaults might be sucky, you are able to change them.
> >
> >
> >
> >
> > ----------------------------------------------------------------------
> > --
> >