Connecting with IPv6 in Windows 8

IPv6 is the future 

Microsoft, along with other technology companies, has been working on the deployment of IPv6 to ensure that end-users continue to have high-quality Internet access, despite the performance and connectivity limitations brought about by IPv4 address exhaustion

The most immediate benefit of IPv6 is that it provides more than 3×10³⁸ IP addresses, enough for every person to have billions of addresses all to themselves, or enough to give every star in the universe a unique address. This will allow the Internet to grow and evolve. IPv6 also provides for many security and performance improvements, like built-in support for IPsec. (What happened to IPv5, you ask? Bing can help you find out why it’s being “skipped.”)

Upgrading the entire Internet to IPv6 isn’t something that can be done instantly. It has taken many years to get to where we are today, and we still have many years of work to do. Currently, around 1% of devices can connect to the Internet using only IPv6.

During the transition period, most networks will fall into three categories:

• IPv4-only networks. This is probably what you have today, as most Internet Service Providers have only just started rolling out IPv6 support. Many devices that connect to the Internet might only support IPv4 as well.
• IPv4 and IPv6 networks (dual-stack). This means your Internet Service Provider is configuring your PC with both IPv4 and IPv6 addresses. This model is common in cable and dial-up networks that are transitioning.
• IPv6-only networks. This means your Internet Service Provider is configuring your device with only IPv6 addresses. Because many websites are still only on the IPv4 Internet, ISPs must use a translation device to allow access from your IPv6 network to the IPv4 Internet. This device is called a NAT64. This mode is becoming popular in the mobile environment, because having only one kind of Internet Protocol between the mobile device and the operator’s infrastructure is simpler to deploy and cheaper than a dual-stack configuration. Also, mobile operators are feeling the IPv4 address exhaustion pinch most severely. Here is a basic diagram of this configuration:

You might be wondering what kind of connection you have right now. We have a widget at the bottom of this post that can show you.

Windows 8 is designed to ensure connectivity across all types of network configurations. In Windows 8, you can launch DNS look-ups using the Resolve-DNSname cmdlets in Windows PowerShell. Open up PowerShell and run the below command, and you will see both IPv6 and IPv4 records returned. Only websites that support IPv6 will have IPv6 records

Windows 8 on IPv4-only networks

On an IPv4-only network, devices are configured with IPv4 addresses only. This model continues to work in Windows 8 as it has in the past. In addition, Windows hosts also provide IPv6 connectivity by tunneling that traffic inside various transition technologies – an example of which is Teredo, where IPv6 packets are encapsulated in IPv4 UDP packets. Now that we are starting to see the emergence of IPv6-only servers and services, Windows 8 automatically attempts IPv6 connectivity when the server does not offer an IPv4 address. Note that Teredo is enabled by default only on non-domain networks, and Teredo may not be available if your network blocks UDP

Windows 8 on dual-stack networks

During the transition period, dual-stack networks will be the common deployment model. On a dual-stack network, devices will be configured with both IPv4 and IPv6 addresses.

Our primary focus during this transition has always been to minimize the impact of the transition for everyday users. It shouldn’t matter whether your connection is over IPv4 or IPv6. You should have an Internet experience that is fast and reliable, with little evidence of the IPv6 transition, so you can just enjoy the content.

At the same time, it’s also a priority for us to help the IPv6 transition move ahead. To this end, Windows prefers native IPv6 connectivity over IPv4 connectivity, if both connection modes are available.

In summary we have the dual goals of ensuring a reliable user experience, and enabling the IPv6 transition. As you might imagine, this can sometimes involve subtle tradeoffs, which have been the subject of much debate in the Internet community.

In an effort to sort out those sometimes competing goals, major websites around the world--including Bing.com, Microsoft.com, and Xbox.com–organized an event called World IPv6 Day last year. During this one-day test of the IPv6 Internet, participating websites turned on IPv6 in addition to IPv4.

The good news is that most things worked. All that goes into the Internet’s correct functioning—servers, end-user devices, and content delivery networks—were able to work at scale without issue.

However, we also observed that a small subset of the population (0.01% of the world) was misconfigured with IPv6, seemingly because of a router or ISP issue. That’s not too surprising, as IPv6 is a fairly new technology, and mistakes happen. But for those unlucky users, it could cause a significant impact on everyday experiences with the Internet.

Ready for the future of IPv6-only networks

On an IPv6-only network, the best way to improve a user’s experience is to increase the number of services and experiences that are available over IPv6. On such a network, access to the IPv4 Internet is through a NAT64. These devices can be a fragile point of failure for connectivity, and can have severe performance limitations that lead to dropped packets. They also break IPv4 peer-to-peer connectivity, needed for some multiplayer games.

Across Microsoft, we have done a lot of work to enable the growth of IPv6 deployments, both in enterprise and Internet settings. One of our most important efforts is to ensure that our server products support IPv6. IPv6 support is part of our Common Engineering Criteria (CEC). This is part of a broad company-wide commitment to customers that our business products, such as Exchange Server and SharePoint, support IPv6 in either dual-stack or IPv6-only configurations. Most Microsoft products built since 2007 have supported IPv6, but you can find out about IPv6 support in other Microsoft products on Technet. Through this effort, developers and solution providers can support IPv6 in their own products

Microsoft is also working on IPv6 support for our own services. Earlier this year, the Internet Society announced the World IPv6 Launch, a major milestone in the process of upgrading the Internet to IPv6. In June, Bing and other websites will start serving traffic over IPv6 on a permanent basis. Hardware vendors are working on IPv6 support in home routing devices, and many ISPs will start large-scale deployments of IPv6. CDNs (content delivery networks) have also started enabling support for IPv6 within their networks.

With the release of Windows 8, some of our infrastructure services will deploy IPv6 support.
Windows Update is a critical service providing ongoing support and updates to millions of users every day. More and more PCs are going to be connected to mobile broadband networks, where IPv6-only is a popular configuration. We have to make sure that downloads are reliably available to you on those networks.

For this reason the Windows Update service now supports both IPv6 and IPv4. Windows Update utilizes CDNs for worldwide distribution of updates and we are partnering with them to enable IPv6 support. Windows 8 will use IPv6, if available, to download Windows Updates so that users always get the best possible connectivity when downloading updates

We are working with CDNs to extend IPv6 support beyond Windows 8. Once that work is complete, even Windows 7 and Windows Vista will automatically use IPv6, where it is available, for connecting to Windows Update.

Leading the way

Windows 8 is connected and ready to use, and our support of IPv6 is a key part of ensuring that connectivity for years to come. Because IPv4 wasn’t designed to handle the scale of connectivity today, the Internet is undergoing a radical change in its foundation. Every connection to every website, every multiplayer game, and every video call will gradually move to IPv6

As part of that transition, Microsoft is leading the way by ensuring that Windows 8 provides the most resilient connectivity to the Internet while providing IPv6-ready products and services.