The Number Resource Organization warned Monday that the number of available IPv4 addresses had slipped below 10 percent, with one service predicting that the available addresses will expire in a bit more than a year.

The Number Resource Organization warned Monday that the number of available IPv4 addresses had slipped below 10 percent, with one service predicting that the available addresses will expire in a bit more than a year.

The NRO said that two blocks of IPv4 addresses, representing about 1/256th each of the available addresses, had been given to APNIC, the regional Internet registry for the Asia-Pacific region.

Now, only twelve IPV4 blocks remain. One apiece will be allocated and handed out simultaneously to each of the five regions, leaving seven more to be apportioned by need.

Current IP addresses use the IPv4 format, which assigns users an IP address using four numbers, each from 1 to 256. (8.8.8.8 is an available DNS server IP address administered by Google, for example.) Addresses like pcmag.com are translated behind the scenes into their numeric equivalents, just like 800-DOMINOS equates to an actual phone number. Each new device that connects to the Internet is assigned a new IP address, although home networks can assign their own non-unique IPs via network address translation, or NAT.

In 2008, worldwide organizations began warning that the number of IPv4 addresses was slowly expiring, predicting that they would expire at the end of 2010 or early 2011. That seems to be holding true, with one algorithm predicting that the central registry will run out of IP blocks to assign in just 228 days, and that the final IPv4 IP address will be used in 465 days - January 26, 2012, just before the Super Bowl.

"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 Axel Pawlik, Chairman of the Number Resource Organization (NRO), the official representative of the five RIRs, in a statement. "It is critical that all Internet stakeholders take definitive action now to ensure the timely adoption of IPv6."

IPv6 addresses add an additional level of complexity to the IP address, providing up to 340 billion billion billion billion addresses - enough to provide an IP address for all devices for the foreseeable future.

In 2008, barely any of the Internet had moved to IPv6. Today, the NRO said the shift is becoming more pronounced. In 2010, the five RIRs are expected to allocate over 2,000 IPv6 address blocks, representing an increase of over 70 percent on the number of IPv6 allocations in 2009, the NRO said. In contrast, the number of IPv4 allocations is expected to grow by only 8 percent in 2010.

Small studies by companies like Arbor Networks show that Google is among the leaders in pioneering IPv6 use, helping push the U.S. up to the top among the various geographies that have undertaken the shift.

The U.S. federal chief information officer, Vivek Kundra, also set the end of the government's fiscal year 2012 (July 2012) as a deadline to upgrade external facing servers, such as Web and ISP services, to IPv6. But if some predictions are right, this will be too late.

"Internet wide IPv6 measurements still show relatively little v6 traffic," Craig Labovitz, chief scientist at Arbor Networks, wrote in a recent blog post. "The graph below shows 6to4 as an average percentage of all Internet traffic across ATLAS ISPs. While v6 traffic has climbed dramatically in the last three years (more than a hundredfold), v6 remains less than one twentieth of one percent of all Internet traffic as of October 2010."

Some of the nation's ISPs, however, have begun trials of IPv6; for example, at the beginning of October, Comcast began allowing customers to access IPv6 through one of two tunneling mechanism that encapsulates IPv6 packets inside of IPv4 packets.