Yesterday's Windows update causes IPv4 to be default

[Dan Wing]

> -----Original Message-----
> From: Tassos Chatzithomaoglou [mailto:achatz at forthnetgroup.gr]
> Sent: Wednesday, November 14, 2012 11:16 AM
> To: Dan Wing
> Cc: ipv6-ops at lists.cluenet.de
> Subject: Re: Yesterday's Windows update causes IPv4 to be default
> 
> If this is MS's new way of doing HE, then i'm little bit worried about
> choosing a protocol based solely on connectivity to an external entity.

I concur.  *shrug*.  I would have liked Apple to prefer IPv6 slightly,
but Apple and Microsoft both have good reasons for their implementation
decisions -- I have talked with the engineers from both companies about
how this is implemented on their respective OSs.

Windows 8 does have an exception for RAs for specific IPv6 networks, but 
that is only useful for intra-network traffic (e.g., IPv6 within an 
enterprise or within a home).  I don't know if that exists in the
enhancement to Windows 7, but I expect it does.

-d


> --
> Tassos
> 
> Dan Wing wrote on 14/11/2012 20:58:
> >> -----Original Message-----
> >> From: ipv6-ops-bounces+dwing=cisco.com at lists.cluenet.de [mailto:ipv6-
> >> ops-bounces+dwing=cisco.com at lists.cluenet.de] On Behalf Of Tassos
> >> Chatzithomaoglou
> >> Sent: Wednesday, November 14, 2012 9:00 AM
> >> To: ipv6-ops at lists.cluenet.de
> >> Subject: Re: Yesterday's Windows update causes IPv4 to be default
> >>
> >> http://support.microsoft.com/kb/2750841
> >>
> >> /Assume that a computer is configured to use an IPv6 connection as
> >> the default connection.
> >> Additionally, assume that the computer does not have a connection to
> >> an
> >> IPv6 network. In this situation, it takes a long time for the
> >> computer to connect to an IPv6 site. // // //This issue occurs
> >> because Windows tries the IPv6 connection first. After the connection
> >> fails because of a time-out error, Windows tries the IPv4
> >> connection.// // //After this update is installed, Windows uses the
> >> NCSI functionality to examine the
> >> Ipv6 connection. If the connection is broken, Windows uses IPv4
> >> instead of IPv6./
> > Yep, Windows 8 has been doing that since Windows 8 shipped.  Full
> > details are in my Cisco Live slide deck (I'll have to find a pointer)
> > and a pretty good summary is
> > http://blogs.msdn.com/b/b8/archive/2012/06/05/connecting-with-ipv6-in-
> > windows-8.aspx
> >
> > -d
> >
> >
> >> --
> >> Tassos
> >>
> >> Dick Visser wrote on 14/11/2012 18:46:
> >>> Hi
> >>>
> >>> I looks like yesterday's batch of updates causes Windows 7 to prefer
> >>> IPv4 over IPv6.
> >>> After (automatically) installing the whole lot, one of my users
> >>> complained about connection issues with WinSCP to our web server.
> >>> This runs SSH on IPv6-only. His WinSCP for some reason tried to
> >>> connect over IPv4, without falling back to IPv6.
> >>> I tried "ping www.terena.org" and that also used IPv4.
> >>> "ping -6 www.terena.org" did also work, but I'm pretty sure it used
> >>> to default to IPv6.
> >>> After clearing the cache in WinSCP things started to work again.
> >>>
> >>> I didn't install the updates (about 20, including the Office ones)
> >>> on my own computer, so I had a look at them first.
> >>> One of them is called "No network connectivity on Windows 7-based or
> >>> Windows Server 2008 R2-based client computers when a DHCPv6 message
> >>> is sent that has a duplicated DUID",
> >>> http://support.microsoft.com/kb/2763523, which is the only one that
> >>> mentions IPv6.
> >>>
> >>> Before installing anything, I tried to "ping www.terena.org" and
> >>> that used IPv6 all-right.
> >>> I then installed all the updates except the suspicious
> >>> http://support.microsoft.com/kb/2763523.
> >>> After rebooting, "ping www.terena.org" uses IPv4...
> >>>
> >>> So I guess one of the other updates caused this; I'm now booting up
> >>> a VM to investigate which one exactly.
> >>> So far the no other major stuff broke, and it looks like only the
> >>> default has changed, but I'd thought I mentioned it here anyway,
> >>> just in case...
> >>>
> >>> Anyone else has seen IPv6 issues on Windows since yesterday?
> >>>
> >>>
> >>>
> >
> >