APNIC (Asia Pacific Network Information Centre) is eligible to request two large blocks of IPv4 (Internet Protocol, Version 4) addresses, because users have been snapping up its existing stock quickly enough, according to Leo Vegoda, manager of number resources at the Internet Assigned Numbers Authority. Because there are only seven of these large blocks left, that allocation to APNIC would activate a policy for the IANA to hand out the last five blocks to the five regional registries, Vegoda said.

Experts have been warning ISPs (Internet service providers) and enterprises for years that IPv4 addresses are destined to run out soon. Various technical fixes have staved off that day, but the assignment of those final blocks would leave the ultimate supply of those addresses tapped out. This would mark a milestone on the path to an Internet based totally on the latest protocol, IPv6.

It typically takes about two business days to fulfill a request by a regional Internet registry (RIR) such as APNIC for more address blocks, and it can be done more quickly if needed, Vegoda said. The IANA does not comment on address allocations until they are made, but "it would certainly be possible for us to process a request before the end of this week," he said. APNIC, based in Brisbane, Australia, was not immediately available to comment on a possible address request.

The timing suggests that predictions that IPv4 addresses will be depleted very soon may be correct. Martin Levy, director of IPv6 strategy at ISP Hurricane Electric, predicted last week that the IANA's stockpile would be exhausted this week. At the same time, two online "clocks" that estimate the date of IPv4 depletion are showing that this event should have passed already or would occur very soon. On Monday, . A long-running IPv4 clock at Potaroo.net .

The IANA is the part of ICANN (Internet Corporation for Assigned Names and Numbers) that allocates IP addresses to the RIRs. The regional organizations, in turn, fulfill requests by ISPs and other customers in their regions for smaller blocks of addresses. After the IANA hands out the last of its so-called "/8" blocks, each of which contains about 16 million addresses, the RIRs will have no additional supply to turn to after they have fulfilled their customers' requests.