Back in mid-January, I wrote about the scheduling of World IPv6 Day, June 8, 2011, which is intended to provide a large-scale test of the Internet infrastructure changes needed to support Internet Protocol version 6 [IPv6]. As I wrote in that post, we were nearly out of available addresses in the 32-bit IPv4 format.
Now, according to a post today on the “Law & Disorder” blog at Ars Technica, the last available blocks of IPv4 addresses were allocated this morning to the five Regional Internet Registries [RIR]; these organizations are responsible for issuing addresses to users in their geographic areas. The RIRs still have addresses allocated to them that have not yet been used, but those will eventually be used.
In a ceremony in Miami this morning, the final five blocks of IPv4 addresses were given out to the five Regional Internet Registries that further distribute IP addresses to the far corners of the planet. The five RIRs still have tens of millions of addresses as working inventory, but once those addresses are given out, it’s over.
The RIRs differ in the size of their pools of free addresses, and also in the rate at which they are being used. APNIC, which is responsible for the Asia/Pacific region, is closest to the edge, and will almost certainly run out of IPv4 addresses this year. On the other hand, LACNIC (Latin America and the Caribbean) and AfriNIC (Africa) can probably carry on for a few years. ARIN (North America) and RIPE (Europe, Russia, and the Middle East) are somewhere in between.
The Internet Engineering Task Force [IETF] has been working for a number of years on transition mechanisms to ease the IPv4 to IPv6 switch, and there is no reason to expect any major problem in the near term because there are no more IPv4 address blocks available. But I hope it will serve as a wake-up call to the many organizations that have been dragging their feet about moving to IPv6. There is still enough time to get things together, but the grace period will not be indefinite.
Incidentally, Ars Technica also has a good introductory article (dating from 2007) on the move to IPv6.
Update Thursday, 3 February, 22:25 EST
Wired also has an article on the allocation of the last IPv4 addresses, which has a little more explanation of some of the implications of the transition.