IPv6 ... Index for the world

Microsoft sees strategic value in IPv6 because, among other things, it eases the process of setting up peer-to-peer (P2P) gaming programs and migrates customers to IPv6 as IPv4 addresses get used up. On the down side, however, IPv6 can also double Vista's attack surface. Several leading security analysts are recommending you disable Vista's IPv6 capability by turning off Teredo tunneling through the network.

Teredo/Miredo is available for the most popular operating systems allowing you to penetrate popular NATs and Firewalls. It can likely allow you bypass any blocking or censorship policies on your network. It even works from China, so you can use it to read your favorite blocked sites. Improper use can be dangerous to network managers.

Lockeed Martin is one major company rolling out IPv6, "eating their own dog food." However most enterprises realize making IPv6 do every single thing that IPv4 can do is no easy task.  Many switches (which don't need to support IPv6 to transport IPv6 packets) only support management over IPv4. Firewalls and load balancers lack functionality, and although a lot of software already supports the new protocol, there is also a great deal of software that doesn't. Not to mention people having trouble getting network-attached printers to work. Unless it's possible to make the modifications in-house or get a vendor to make them promptly, supporting IPv6 often requires workarounds in the form of reverse proxies. For the time being, most companies are still waiting to see how this develops. Google is an LIR (Local Internet Registry) and has snapped up a huge block of IPv6 addresses. They own about 79 billion billion billion addresses (that's 2 to the 96^th power). IPv6 will allow Google to index every device on the planet (think M2M).