I am presenting at TechMentor in August on IPv6

If you are interested in visiting the Pacific Northwest in August (which is a great time of the year to visit!) then come check out the TechMentor Conference.This year it will be held at Microsoft HQ in Redmond on August 20-24, 2012.

The list of presenters is pretty impressive like Don Jones, Mark Minasi, Bruce Rougeau and Greg Shields. You will also get to hear from me on IPv6 (of course) and lots of other great speakers.

Here's a small sample of the topics that will be covered at TechMentor this year:

• Virtualization
• Application Delivery
• MCITP Certification
• PowerShell

You can register at: http://bit.ly/TMRD2012
You can use the discount code of TMRTU for a $300 discount off the 5 day value package.
- Ed

Windows 8 and IPv6

For those that missed the Microsoft blog post by Chris Palmer explaining the IPv6 support that Windows 8 will have it is worth a read. It is important enough that Steven Sinofsky posted it as a guest blog entry on his building Windows 8 page, which is pretty cool. With Windows 8 now RTM understanding how IPv6 works in the Windows OS environment is pretty important. This is the third client OS release from Microsoft with comprehensive IPv6 support (Vista, Windows 7 and now Windows 8) and the server side is equally as impressive (Windows Server 2008, 2008R2 and now 2012) so there is no excuse not to understand and start working with IPv6. After all, you have had since 2007 (Vista's release) to start working on your IPv6 skills!

The important take away from the post to me was that Windows 8 will not have full RFC 6555 (Happy Eyeballs) support in the way many in the industry wanted (Dan Wing and others.) Happy Eyeballs is an important stop gap solution to resolving much of the end user experience issues that happen when IPv6 isn't work correctly. The issues happen when IPv6 is turned on but broken (routing isn't working for example) but is still preferred over IPv4 connectivity. This situation will become more common as IPv6 is more widely deployed but not as well understood by IT Professionals and helpdesk staff. Their lack of comprehensive understanding of troubleshooting dual stack environments will make this issue more common in the next 1-2 years is my feeling. Hopefully this will change as wider adoption of IPv6 means a better understanding of the protocol and its importance.


In my conversations with many at Microsoft regarding IPv6 and RFC 6555 it comes to light that they see their client OS being deployed and supported much longer than many in the industry. One of the principal concerns with doing a full RFC 6555 implementation was that it likely won't be needed in 3-5 years and because of how RFC 6555 works it makes it much tougher to debug application behavior on the client. This is a huge concern for Microsoft as custom applications deployed in Enterprise environments is a large part of their business. Making client behavior different depending on the application that is running and per session spells disaster in the QA testing area.


There are other considerations too about why they chose the path they did for doing such a limited support of RFC 6555 but the reality is... it doesn't matter. You can't change it, Windows 8 will make use of a modified RFC 3484 solution outlined in Chris' blog post and quoted below:

"Windows 8 tests IPv6 connectivity when you connect to a new network that advertises IPv6 routabilty, and it will only use IPv6 if IPv6 connectivity is actually functioning. This approach is a modification of our implementation of RFC 3484. Instead of sorting addresses as a result of policy, we use the actual state of the network as input to our algorithm. On a misconfigured network, this approach improves the experience not only for browsers but also for apps that connect to dual-stack destinations using standard Windows APIs.
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.
To make sure that Windows 8 does not cause problems on enterprise networks, the functionality has two safeguards:

• If the enterprise has provided specific routing information to a particular destination, then Windows 8 will honor that preference, regardless of the connectivity determined by Windows. In enterprise environments, Windows assumes that network administrators who configure such routes specifically thought it was a good idea to use those routes.
• This change isn’t implemented on networks with web proxies. In these networks, the proxy provides connectivity to the Internet; so end-to-end testing of IPv6 connectivity is not useful. Instead, Windows 8 simply opens connections to the proxy in the most efficient manner possible.

In this way, we’ve ensured that apps and experiences on Windows 8 can remain reliably and speedily connected to the Internet throughout the IPv6 transition, even if your local network is misconfigured."

So there you have it. More details about how it all works can be found in Joseph Davies' Understanding IPv6, Third Edition, an excellent reference book on how Microsoft has implemented IPv6 in Windows. Full discloser, I was the technical editor for the book.
- Ed

Great IPv6 Subnetting Article by Chris Grundemann

If you want a great explanation of IPv6 subnetting then head over to Chris Grundemann's article, he does an awesome job of explaining the principal different in thinking between IPv4 and IPv6 addressing and subnetting design. It is well worth the read.
- Ed

Understanding IPv6, Third Edition is now available!

Microsoft Press has released the new book Understanding IPv6, Third Edition by my friend Joseph Davies. I was fortunate enough to be asked by Joe to be the technical editor of the book and I am very excited about it now being available. Joe has done a great job covering some pretty difficult topics around IPv6 and if you are an IT Pro and doing Microsoft infrastructure architecture, design and deployment you really need to get this book. Why?

First, it has been updated for Windows 8 and Windows Server 2012 and some of the specific IPv6 behavior those two OS's will have verse previous versions of Windows. Second, it has updated recommendations on best practices for deployment in DirectAccess environments and also updated references to RFC's. The last point isn't trivial as the RFC landscape around IPv6 is actually changing and has been moving around a lot within the last 3 years or so.

Finally, you will need a good technical reference around the IPv6 protocol and how it is implemented in Windows and this is the ONLY book that provides that. It was written by someone who has intimate access to the Windows COSD team (they write the network stack for Windows) and I think Joe does a wonderful job making a rather difficult subject matter something that can be understood quickly. Best of all, you don't have to read it end to end, it was designed to be read in chapters as they are relevant to you and what you are trying to do.

It is available from Amazon and at the O'Reilly / Microsoft Press site. The first chapter is available as a sample download too.

The book chapters are:
Chapter 1: Introduction to IPv6
Chapter 2: IPv6 Protocol for Windows
Chapter 3: IPv6 Addressing
Chapter 4: The IPv6 Header
Chapter 5: ICMPv6
Chapter 6: Neighbor Discovery
Chapter 7: Multicast Listener Discovery and MLD Version 2
Chapter 8: Address Autoconfiguration
Chapter 9: IPv6 and Name Resolution
Chapter 10: IPv6 Routing
Chapter 11: IPv6 Transition Technologies
Chapter 12: ISATAP
Chapter 13: 6to4
Chapter 14: Teredo
Chapter 15: IP-HTTPS
Chapter 16: NAT64/DNS64
Chapter 17: IPv6 Security Considerations
Chapter 18: DirectAccess
Chapter 19: Deploying IPv6 on an Intranet
Chapter 20: IPv6 on the Microsoft Corporate Network
Appendix IPv6 RFC Index
Appendix Testing for Understanding Answers
Appendix Setting Up an IPv6 Test Lab
Appendix IPv6 Reference Tables
Appendix Link-Layer Support for IPv6
Appendix Windows Sockets Changes for IPv6
Appendix Mobile IPv6
Appendix Teredo Protocol Processes

So there you have it, my shameless book plug. Honestly, I really do believe you will get great value from Joe's book if you have to do any work around IPv6 and Windows at all. Given everything that is happening on the Internet that should be a LOT of people!
- Ed

Follow up from Microsoft TechEd Europe

There were some additional questions I got at Microsoft TechEd Europe plus some great feedback I wanted to share about my presentation.

First off, thanks to everyone who attended my session in Amsterdam, it was a thrill to present to around 500 delegates and I appreciate all the survey feedback too (and the positive survey ratings!)

For everyone asking about how to get started and reference materials, in my previous post from my Microsoft TechEd North America presentation I have references for books, websites to get IPv6 tunnel broker services and even client host agents to get IPv6 up and working on your Windows 7 machine. To avoid duplication please just pop open that blog post to get that info.

One of the requests I got was for a white paper on how to get started on planning and deployment, something that could specifically be used with management. I don't have a specific white paper to provide however there are some excellent resources out on the web that might provide enough information to help in this area.

Specifically, you can look through both ARIN and RIPE's excellent websites for materials that might match your need requirements. In addition, ARIN maintains a great WIKI on IPv6 at http://www.getipv6.info which is well worth some time to review. There are commercial companies that can provide specific planning and deployment recommendations but those services are obviously not free.

If you are interested in seeing my session but you missed it in person my TechEd North American session is posted (audio and slides only.) I don't know if they will be posting the one from TechEd Europe or not.

- Ed