The IPv4 address secondary market has emerged since last spring, when Microsoft made a splash by purchasing 666,624 IPv4 addresses from Nortel during its bankruptcy proceedings. Microsoft spent $7.5 million on Nortel's IPv4 addresses, giving the market an evaluation of $11.24 per IPv4 address. Microsoft made this IPv4 address purchase even though its Bing search engine is one of the founding participants of World IPv6 Launch Day.
Since then, several large bankruptcy-related IPv4 address sales have been approved. In December, for example, Borders sold 65,536 IPv4 addresses - what's called a /16 -- to software provider Cerner for $12 each.
Some IPv4 address sales - or transfers as Internet policymakers prefer to call them - are being recorded through official channels such as the American Registry for Internet Numbers (ARIN), which allocates IPv4 and IPv6 address space to North American ISPs and other network operators.
As of March 31, ARIN had recorded 88 IPv4 address blocks transferred that total more than 4 million IPv4 addresses. Two of these transfers involved what are called /12 blocks of addresses, with more than 1 million IPv4 addresses each. (These IPv4 address sales - which are known as 8.3 transfers in ARIN parlance - are different than transfers of IPv4 addresses that occur as the result of a merger or acquisition, which ARIN calls 8.2 transfers.)
"The largest amount of space being transferred is because companies are going through bankruptcy proceedings," said John Curran, President and CEO of ARIN, which still has more than 77 million unused IPv4 addresses in its coffers to dole out for free. "This [transfer process] provides them with a way to make sure they achieve an appropriate value for their number resources. They have to do work to de-configure the addresses and make them available to the community, so it makes perfect sense for them to be compensated for that work."
Curran said some network operators prefer to buy IPv4 address space through an 8.3 transfer rather than receive it free from ARIN because of differing policies over the two types of allocations. Network operators must justify their need for IPv4 addresses for either process, but they can receive 24 months' worth through an 8.3 transfer and only 90 days' worth through a free allocation.