We have been learning for years that we are running out of IPv4 addresses. But we are not running out — they are not all in use. It is simply that some organizations have addresses to allocate to organizations that are subordinate. More substantially, I submit this is an artificial lack of addresses caused more by the mismanagement of their allotment than by lack.

There are 221 groups, each with about 16.7 million addresses available for allocation. There are definitely plenty of apparatus accessible through the Internet — but are there more than 3.7 billion of them? I am not talking about apparatus used to reach the Internet. I am especially concerned merely with those devices right reachable through the world wide web, including servers (internet, email, FTP, DNS, reverse proxy), routers, and firewalls. It is a hard question to answer because everybody is busy counting apparatus with access, not devices that merely provide services as it occurs.

But let us get back to the actual problem and set the raw numeric comparisons. The problem is not that all the IP addresses are in use; it is that they all have been allocated. A lot of those allotments are wasteful, and millions of addresses are fresh. A less type man might say they are being hoarded.

Let us review how IP addresses get allocated. At the top, the Internet Assigned Numbers Authority (IANA) allocates blocks of addresses to the Regional Internet Registries (RIRs), of which there are five: ARIN (North America), LACNIC (Latin America), RIPE (Europe, Middle East, Central Asia), APNIC (Asia/Pacific), and AFRINIC (Africa). All available blocks have been allocated by IANA to all those five RIRs, which in turn allocate smaller blocks of addresses to organizations, government agencies, and ISPs. Of special note, APNIC allocated all of its addresses by April 2011. As many as 350 million addresses were allocated to China, apparently in use behind the firewall that was national that nobody can get out or in of. I am not conscious that any of the other four RIRs have reported apportionment of all available addresses.

Let us focus on North America and ARIN, because that is where the majority of the waste originates. Most of the apportionment’s in North America happened before the debut of Classless Inter domain Routing (CIDR) in 1993. Allocations made following the debut of CIDR were done in considerably smaller blocks and so generally better.