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The US Department of Defense has 42 million billion billion billion IPv6 addresses

Just as it did with IPv4, the US Department of Defense has managed to get its hands on a huge chunk of the addresses of its successor, IPv6.

The US DoD has a /13 IPv6 block (the smaller the number, the larger the block). No one else in the world is even close to that. The next-largest block after that is a /19 block (which is already huge). In other words the DoD owns a block 64 times larger than anyone else’s.

But just wait until you see how many IP addresses that really is. (Ok, the headline kind of gives it away, but we’ll expand on that.)

So, how many IP addresses is that?

A /13 block contains 2^115 IPv6 addresses. That is 42 million billion billion billion addresses, or put another way: 42 followed by 33 zeros.


We had to look up what a number that large is actually called: 42 decillion. That was a new one for us…

Further perspective on how large the US DoD IP block is

It can be hard to properly picture such a large number, so here are a few examples to give you some perspective. (Hint, 42 decillion is a positively ginormous number.)

  • If you stacked that many US dollar coins on top of each other, the stack would be 84 billion billion billion km high (52 billion billion billion miles).
  • The height of that stack of dollar coins would be 88 billion times the diameter of the Milky Way.
  • If the US DoD added one new device every second and each got its own IP address, they wouldn’t run out until 1.3 billion billion billion years from now.

We recalculated these numbers three times. They simply seemed too insanely large at first.

Looks like the DoD won’t have a shortage of IP addresses anytime soon… And you can add to this that they already own a huge chunk of the IPv4 address space.

Who owns the largest IPv6 blocks?

For the curious, here is a list of the largest IPv6 blocks on the Internet today and who owns them:

The largest IPv6 blocks on the Internet
Owner Block size Number of IP addresses
United States Department of Defense (DoD) /13 4.2E+34
France Telecom /19 6.5E+32
Deutsche Telecom /19 6.5E+32
Korea Telecom /20 3.2E+32
SoftbankBB IPv6 Network /20 3.2E+32
Australian Government Department of Defense /20 3.2E+32
InterBusiness /20 3.2E+32
TeliaSonera /20 3.2E+32
Telstra Internet /20 3.2E+32
Cable & Wireless Telecommunication Services /21 1.6E+32
Nippon Telegraph and Telephone West Corporation /21 1.6E+32
HiNet Taiwant /21 1.6E+32
Polish Telecom /21 1.6E+32

Source for IPv6 prefix data: SixXS

Other recent IPv6 articles: A crisis in the making: Only 4% of the Internet supports IPv6s