The Domain Internet Groper, or dig, as most of us know it, is considered by pretty much everybody in the ‘nix community to be the replacement to nslookup. And I have long been madly in like with it. Not sure why, though. nslookup has never been a disappointment. Maybe it’s because dig is newer and less known and that helps me feel smart when I use it. Or maybe it’s because it’s not natively supported on Windows OS’ and that …make me feel smart when I use it. Or maybe it’s just better.
When discussing IPv6 addresses folks are often quick to say, “FE80 …that’s link-local.” And it’s true. The prefix FE80::/10 is reserved for link-local IPv6 addressing. But a lot of people overlook the fact that the 10-bit prefix only covers two of the four bits represented by the third character in the address. The ‘F’ and the ‘E’ are always going to be those values but the ‘8’ and the ‘0’ can change.
By now most of us know that the IPv6 address space is 128-bits. That’s 96-bits larger than the 32-bit IPv4 address space. By now most of us also know that the IPv4 address space has (on paper) 4,294,967,265 possible address.
So just how big is the IPv6 address space? Well, it’s 2128 (2 raised to the 128th power). If you do that math on that it works out to 340,282,366,920,938,000,000,000,000,000,000,000,000 possible IPv6 addresses (again, on paper). That number, 340 undecillion, is so large that it’s hard to really wrap your head around. In order to try and get some perspective, consider this:
In an earlier post I offered some perspective on just how big the 128-bit IPv6 address space is. The ridiculousness of the number of addresses offers plenty of opportunity for levity. Earlier today I was thinking about what other ways I could show the size of the address space in a way that was meaningful. Time seemed like a perfectly normal way to try and gain some perspective. Here’s what I came up with: