May 25, 2012, 7:16 AM — A growing number of U.S. carriers and enterprises are hedging their bets on IPv6 by purchasing blocks of unused IPv4 addresses through official channels or behind-the-scenes dealmaking.
The U.S. government, Internet policymakers and leading content providers such as Google, Facebook and Yahoo are encouraging network operators to adopt IPv6. In particular, proponents of the new version of the Internet Protocol are promoting World IPv6 Launch Day, an event scheduled for June 6 that requires participants to permanently enable IPv6.
But even as many companies plan their migrations to IPv6 - so far, 1,550 Web sites, 45 ISPs and two home router vendors have committed to World IPv6 Launch Day - they are also purchasing hundreds, thousands, even millions of IPv4 addresses to ensure smooth Internet operations during what's expected to be a decade-long transition from IPv4 to IPv6.
BACKGROUND: Need IPv4 addresses? Get `em here
IPv4, the Internet's main communications protocol, has limited address space that is being rapidly depleted worldwide. The replacement protocol, IPv6, has a vastly expanded address space but is not backwards compatible with IPv4. Most network operators plan to run IPv4 and IPv6 side-by-side for years to come in what's called dual-stack mode, and for this set-up they need both IPv4 and IPv6 addresses.
Designed 40 years ago, IPv4 has 4.3 billion addresses that hosts can use to connect directly to the Internet. Initially, IPv4 addresses were given out in gigantic chunks as large as 16.7 million addresses each to the U.S. federal agencies, universities and corporations involved in the original network research that resulted in the Internet. Most of these organizations use only a tiny fraction of their so-called /8 IPv4 address space, and it's now possible for them to resell unused portions for a huge profit.