Happy World IPv6 Day! Today many of the world’s largest websites test out the new frontier of IPv6, a world of virtually limitless network addresses replacing the old IPv4 (which we’ve now used up completely). Major sites like Google and Facebook, along with operating system providers and networking hardware manufacturers believe that 99% of the world’s systems are ready for this impending transition. That’s a rosy view. The truth may be much uglier.
When they talk about these systems being "ready" for IPv6, they mean that the operating system can handle communications using this protocol, and the servers on the other end can handle it and respond properly. Sure, that means that you can still Facebook away to your heart’s content. Mark Zuckerberg doesn’t want to admit it, there’s a lot more to the world than Facebook.
The problem is in the "other" software. I have no doubt that all the big players will roll out IPv6-enabled updates, and the big web giants will all do extensive testing and make sure their systems are rock solid. But there is a mountain of small software programs (as well as older programs that people still rely on), and an ocean of small to mid-size websites that were built in a world where the sky was blue and IP addresses maxed out at 15 characters. In many cases, there’s an expectation of even more structure, regarding an IP address as a set of four numbers that don’t exceed 3 characters each.
Huge numbers of websites and web-based applications record the IP addresses of visitors and users. They usually do this for security and/or reporting purposes. Until now, an efficient database design would provide either a char(15) or a varchar(15) field to store these addresses. As IP addresses go from "192.168.100.100" to "2001:0db8:85a3:0000:0000:8a2e:0370:7334", these programs and systems won’t be able to handle them without modifications. Imagine walking up to a vending machine with a "new" US dollar bill that is twice the physical dimensions of a current bill. You definitely wouldn’t get that soda you wanted!
World IPv6 Day is the beginning of a major effort to raise awareness of this transition, but the strongest effort needs to go towards software and website developers. Except for highly specialized networking software, the modifications to accommodate the new format shouldn’t require massive changes, but if they aren’t addressed in advance of the transition, the web will start to break for users and site owners will be scrambling to figure out why.