wouldn't run out of addresses in 2005 and there was widespread skepticism about Huston's results, but still.)

Two years later, in 2005, Geoff Huston was back in Amsterdam for the RIPE-51 meeting with a new presentation, also titled "IPv4 Address Lifetime Expectancy Revisited." In the intervening two years, he had adjusted his model and chose the moment the first of the five Regional Internet Registries (RIRs) runs out of addresses as the moment of truth, rather than the moment the last ISP puts the last address into actual use. This, combined with the sharp increase in IPv4 address use in 2004 and 2005, resulted in two new dates: the IANA pool would run out on August 5, 2012 and the first RIR would run out of addresses on May2, 2014. Of course that didn't quite unring the bell from two years earlier—fool me once...

Since that time, Huston's automatically generated predictions have climbed up to (at least) 2016 and then gone back down again, with the current predictions estimating the day the Internet Assigned Numbers Authority (IANA) gives out its last block of 16,777,216 addresses to one of the RIRs to be July 1, 2011, and the day the last IPv4 address is given out by an RIR as January 20, 2012.

It's this first projected date that is getting all the attention right now. There are 221 usable blocks of 16.8 million addresses ("/8s") in the IANA global pool. 205 have been given out to RIRs or large organizations such MIT, Apple, HP, and especially the US