The stockpile of unused IPv4 addresses in North America has fallen so low that there's now a waiting list.
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The writing's on the wall about the short supply of IPv4 addresses, and IPv6 has been around since 1999. Then why does the new protocol still make up just a fraction of the Internet?
The organization that assigns Internet addresses in the U.S. plans to raise the bar for getting them as the supply of IPv4 (Internet Protocol, version 4) addresses nears exhaustion, raising the specter of aggressive speculation on a soon-to-be-rare resource.