In late January, the Number Resource Organization (NRO) warned that IPv4 addresses were drying up, with less than 10% unallocated – a figure that has shrunk rapidly over the last nine months. The organization now reports that two more blocks of IPv4 addresses have been assigned, putting the number of vacant addresses below 5%.

"This is a major milestone in the life of the Internet, and means that allocation of the last blocks of IPv4 to the RIRs is imminent," said NRO chairman Axel Pawlik. He continued by urging all Internet stakeholders to take action now by adopting IPv6, the "next generation" of the Internet Protocol, which offers infinitely more address space. IPv4 (32-bit) gives up to 4.3 billion addresses, whereas IPv6 (128-bit) provides 340 undecillion addresses (340 billion billion billion billion – that's 36 zeros).

The NRO says that five blocks of IPv4 address will be distributed simultaneously to the five Regional Internet Registries (RIRs) – and it won't take long until they're gone based on current depletion rates. Should that occur without adequate preparation, the NRO worries of a "chaotic scramble for IPv6" that could spike Internet costs and threaten the stability and security of the global network.