Time to Fly: IPv6 Demystified Part IV

By James Hanback You now know what an IPv6 address (IPv6) is. You also know how to identify different types of IPv6 address and how to subnet an IPv6 block. Now it’s time to set up IPv6 on a network. Maybe your boss finally took an interest in you and asked what the whole World IPv6 Launch anniversary was all about. Maybe you have decided it’s now that you want to put into practice all the topics you have studied in pursuit of your certification. You are now ready to implement IPv6 in your network, whatever the reason.
You may also think you are ready to throw out old IP version 4 (IPv4).
It’s possible that even though you may be ready, your service provider networks, network services that are connected to your company’s network or end users who connect their (officially approved) devices to the company’s network, might not be ready. How can you balance your desire to move forward in the name of progress and your company’s need for IPv4 to stay on its feet?
It is possible to configure IPv6 alongside your existing IPv4 network, and then make the transition as IPv6 adoption grows. There are many ways to accomplish this task. First, I want to remind you to buckle up your safety belt. Also, make sure your tray tables and seat backs are in the correct positions. We are about to take off and there is much to talk about.
Flying the Direct Route with Dual Stacks
The easiest way to configure IPv6 and IPv4 is to use dual-stack devices. A dual-stack device can have both an IPv4 and one or more IPv6 addresses. A dual-stack device can be configured with both an IPv4 address and one or more IPv6 addresses. The device can also be configured to operate on two separate Transmission Control Protocol/Internet Protocol (TCP/IP/IP) stacks. Dual-stack devices cannot send IPv6 traffic over an IPv4 or IPv6 network. This is a good reason not to disable IPv4 stacks while you implement IPv6.
Let’s say, for example, you have several Windows 7 Professional workstations configured and a file server with IPv6 addresses within the same prefix. When you see results that indicate a zero percent loss, you ping between these workstations. You are so happy that you open the Local Area Connection Properties dialog from your own workstation and deselect the Internet Protocol Version 4 (TCP/IPv4) stack. Then click the OK button. What now? Now what? You can still ping the server from other Windows 7 Professional workstations if you have IPv6 enabled. What happened?
The reason is that file server’s file-sharing services are not working on the IPv6 stack. To regain access, you can easily disable the IPv4 stack from your workstation. You’ve now learned a valuable lesson. Just because you are IPv6-ready does not mean that the rest of the globe has gotten on board. It is a good idea to operate in dual-stack environments until IPv6 surpasses IPv4’s ubiquity.
How do you set up a dual-stack device with multiple stacks? The following screen shot shows how a typical Local Area Connection interface can be configured to simultaneously use both an IPv4 and an IPv6 network.

Let’s say that the PC is already configured for IPv4. Windows will display the following properties dialog if you double-click Internet Protocol Version 6 stack (TCP/IPv6).

As you can see, configuring an IPv6 adress in Windows 7 Professional is very similar as configuring an IPv4 adress in the same. This configuration requires an IPv6 adress, an IPv6 subnet prefix, and an IPv6 default.

Author: Kody