Internet administrators were 99.9999% sure that World IPv6 Day would go by without any real problems. Of course, when you're dealing with something as big as the Internet, even six nines of up-time could mean hundreds of thousands of users with trouble. So far, though, all is well.

At noon Eastern time, all the dual-stacked IPv4/IPv6 sites on the Réseaux IP Européens' (RIPE, French for "European IP Networks") IPv6 Eye Chart are checking in green. This means that these major Web sites are working correctly both for people using the traditional Internet Protocol version 4 (IPv4) Internet and users working with IPv6. This was one of the project's major goals. The last thing Internet network system operators wanted was to find that their IPv6 support was breaking the Internet for the vast majority of users.

Breaking the Internet would have been "Bad." There's a lot of network administrators out there now who are no longer holding their breath.

That's great as far as it goes, but there's more to the story than IPv4 clients being able to talk to hosts that have enabled IPv6 as well as IPv4. The Internet Society's Participants Dashboard, which checks up o IPv6 Day participants from servers based in the United Kingdom (UK) shows that while IPv4 users connecting along at 100%, things aren't so hot for IPv6 users.

For people using IPv6 from their home or office, 94% of sites aren't showing up correctly with AAAA address records on the Internet's master address list: the Domain Name System (DNS). AAAA records are used to store mappings between hostnames, for example, www.google.com, and IPv6 addresses. Without a valid AAAA record, clients that rely solely on AAAA for address resolutions can't reach these sites. That said, since most PC TCP/IP networking stacks fall back to using IPv4's A record for DNS address resolution, most users won't even see this problem. This issue will need to be dealt with by the various sites in due time.

What's more trouble something though is that 92% of the sites aren't reachable by IPv6. Most of these are minor sites, but it still spells out that more work needs to be done at these sites before they're ready for the IPv6 Internet.

Be that as it may, Hurricane Electric, a leading IPv6 ISP, tells me that they've seen "saw a significant upswing in native IPv6 bandwidth being seen on its global IPv6 backbone." By significant, Hurricane means over 300% more IPv6 traffic than usual.

Arbor Networks, an Internet security company, is also monitoring IPv6 traffic. Arbor is focusing on exactly how IPv6 traffic is being transferred across the Internet. According to their numbers, 6in4 is the leading method used by people to use IPv6. 6in4 uses an IPv4 link to encapsulate IPv6 traffic in a tunnel. It's often used by people when they don't have a direct IPv6 Internet connection. Similar methods, such as 6to4, use the same idea for the same job.

Native IPv6 and Teredo are fighting it out for the rest of the traffic. Teredo is another IPv6 tunnel technique. It hides IPv6 packets within IPv4 User Datagram Protocol (UDP) messages. Teredo is primarily used by Windows Server 2008 and Windows 7 users as a way to bridge over to the IPv6 Internet.

Behind the scenes, I'm keeping in touch with ISP and IPv6 network administrators and help desk staff and they're seeing no real trouble either from the Internet administration viewpoint or from their users. To quote one of my network engineer friends at a tier two ISP, "My Customer Support team has told me that it [World IPv6 Day] has turned out to be a non-event for them, so this counts as a big win for the IPv6 Internet to me!"

Exactly so. We now know that the IPv6 Internet can co-exist peacefully with the IPv4 Internet. That's a darn good thing since we can look forward to more than a decade of the two them working side by side as the older IPv4 Internet slowly fades away.

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