Yesterday's Windows update causes IPv4 to be default

Mike Jones mike at
Wed Nov 14 21:12:18 CET 2012

On 14 November 2012 19:16, Tassos Chatzithomaoglou
<achatz at> wrote:
> 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.

The only real detail I could find about this testing was the following:
Windows 8 performs the network connectivity test when you first
connect to a new network; it caches this information and repeats the
test every 30 days. The actual test for connectivity is a simple HTTP
GET to an IPv6-only server that is hosted by Microsoft. (For standards
buffs, this is implemented between rules 5 and 6 of destination
address sorting in our implementation of RFC 3484.) Windows performs a
similar network connectivity test for IPv4 connectivity. If both IPv4
and IPv6 are functioning, IPv6 will be preferred.

Anyone know of a more detailed write-up on this "functionality"?

- Mike

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