Earlier this week I wrote how European IPv4 addresses have now all been allocated. The IPv6 address space is extremely bigger than IPv4 is. IPv4 has 2^32 possible addresses, as they have a length of 32 bits. IPv6 is 128 bits long, allowing 2^128 addresses.

We have an IPv6 address with our fiber to the home connection (currently 500Mbit symmetrical, which is actually a step down from the 1Gbit symmetrical we had before). I asked our provider what type of address allocation they use for IPv6. They allocate a (currently recommended) /48 block to us. A /48 IPv6 block contains 2^(128−48) = 2^80 addresses. The total IPv4 address space is 2^32 addresses. So we actually have an available address space at home that is 2^16 (65.536) times larger than the square of the total number of IPv4 addresses (2^16*2^32*2^32=2^80). These are mind bogglingly large numbers.

2 reactions on “Enormous Private Address Space With IPv6

  1. Internet providers here in Canada have always charged an (enormous) surcharge for having a (single) static IP address assigned to your connection. This was somewhat defensible under IPv4, but under IPv6 it’s clearly not.

    • Yes, some Dutch providers were like that too. Luckily my first ISP (Demon Internet) entered the Dutch market late ’96 with the promise of a fixed IP address for every customer. So I’ve always had the luxury of having my own IP address after I said my university’s dial-in service farewell. I was able to run my site and blog on a server under my desk for a decade because of it, (and because I early on had an ADSL connection), until I switched to a hosting package in the fall of 2007.

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