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Where did all the IP numbers go? The US Department of Defense has them

There have been voices raised that we are running out of IPv4 addresses for some time now. So who has taken them? After discussing this at a coffee break here at Pingdom, we were curious. Are there are any “big spenders” who have allocated a huge share of the IP space for themselves? Yes there are.

When looking at the assigned IP blocks at IANA (Internet Assigned Numbers Authority), what becomes immediately clear is that the US Department of Defense has a significant number of large IP blocks. We only looked at /8 IP blocks, the largest blocks you can get, and there are 12 of them assigned to the US DoD and related organizations. Each /8 block holds 16,777,214 IP addresses, so the DoD have in effect allocated more than 200 million IP addresses. That should hold them for a while.

The closest any other corporation comes to this are Level 3 Communications and Hewlett-Packard, with two /8 blocks each. The DoD-owned IP blocks together with the 26 corporations and universities who have their own /8 blocks hold more than 671 million IP addresses.

These were all early land grabs, most of them made between 1991 and 1995.

Some notables among the companies with one /8 IP block are Apple (but no Microsoft in sight), IBM, Halliburton and the Ford Motor Company.

Companies and organizations with IPv4 /8 blocks from IANA
Owner Blocks ~IP addresses
US Military (Department of Defense etc.) 12 201 million
Level 3 Communications, Inc. 2 33 million
Hewlett-Packard 2 33 million
AT&T Bell Laboratories (Alcatel-Lucent) 1 16 million
AT&T Global Network Services 1 16 million
Bell-Northern Research (Nortel Networks) 1 16 million
Amateur Radio Digital Communications 1 16 million
Apple Computer Inc. 1 16 million
Cap Debis CCS (Mercedes-Benz) 1 16 million
Computer Sciences Corporation 1 16 million
Deparment of Social Security of UK 1 16 million
E.I. duPont de Nemours and Co., Inc. 1 16 million
Eli Lily and Company 1 16 million
Ford Motor Company 1 16 million
General Electric Company 1 16 million
Halliburton Company 1 16 million
IBM 1 16 million
Interop Show Network 1 16 million
Merck and Co., Inc. 1 16 million
MERIT Computer Network 1 16 million
Massachusetts Institute of Technology 1 16 million
Performance Systems International (Cogent) 1 16 million
Prudential Equity Group, LLC 1 16 million
Société Internationale De Telecommunications Aeronautiques 1 16 million
U.S. Postal Service 1 16 million
UK Ministry of Defence 1 16 million
Xerox Corporation 1 16 million
40 671 million

The table doesn’t include the blocks allocated for RIRs and other special purposes.

One thing that strikes you is the low number of ISPs on this list. This is most likely due to their late appearance on the internet when it was harder to reserve big IP blocks, forcing them to settle for smaller blocks.

That the US Department of Defense has such a huge amount of the IPv4 address space is partly due to historical reasons: They developed the internet in the first place (ARPANET) and have a strong vested interest in the evolution of the internet.

Of course, IPv6 is on its way which will end this discussion for good (or at least for a looong time), but with a bit of rearranging IPv4 could probably last us for quite a while yet.

A small note:
We only looked at IANA’s own numbers. We didn’t look at the Regional Internet Registries such as ARIN or RIPE, partly to limit the scope of the research and partly because we were only interested in the huge /8 IP blocks. There are only 256 /8 blocks, and many of these are reserved for special purposes.


There are 126 Class A networks FYI


jbenson.. the point is that unlike level3, the dod actually has limited use for public ip space. should anyone justify having such a vast range, it would be a communications company and not the military, who are likely to keep their information private for your own sake.

Royal Pingdom
Royal Pingdom

@ jbenson2: It's not like we're comparing them in the way you seem to be suggesting. It's just an observation. The main point of the article is that the US military has 12 of a very limited number of /8 IP blocks in IPv4, which is a huge share.


What is your point? Comparing the entire US Military to Level 3 Communications is a bit ludicrous. I'm surprised the match-up is that close: 12 vs 2.

Dustin J. Mitchell
Dustin J. Mitchell

Surely you've seen this comic: I've never heard any numbers on actual usage by DOD. I kinda doubt that each Abrams Tank has a publicly-routable IP address :). I wonder if they're just hanging onto the allocations because they have them and because there isn't really a shortage of IPv4 addresses.


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