The clock has stuck midnight. While your carriage may not have turned into a pumpkin, we really are out of IPv4 addresses on the Internet.
Oh sure, in North America, a few addresses left haven’t been spoken for yet, but they’ll be gone by the end of 2011. And you can buy IPv4 addresses for your growing enterprise for a little while. But the chimes of midnight are ringing in the air: You must start switching over to IPv6.
It’s not going to be easy, and you probably want to consider the transition in phases.
I recommend you start your IPv6 deployment by making your external Web, DNS, and e-mail services reachable from the IPv6 Internet.
The good news, though, is that you don’t need to switch over your intranet to IPv6 anytime soon. Within the confines of your company, you can still use IPv4. You need to move to IPv6 for your gateways, load-balancers, and outward facing Web and application systems, but at least for a while you can get by with IPv6/IPv4 gateways, dual-stack systems, and the like.
In short, you and your network staff need to learn some new technologies. It would be great if IPv6 was simply backwards compatible with IPv4 so we could easily switch over to tomorrow’s IPv6-dominated Internet – but it’s not.