IPv6

An IPv6 address is 128 bits

Every additional bit doubles the number of possible adresses.

There are 340,282,366,920,938,463,463,374,607,431,768,211,456 IPv6 addresses.

Shortening IPv6 addresses

• Leading 0s can be removed

  • 2001:0DB8:000A:001B:20A1:0020:0080:34DB -> 2001:DB8:A:1B:20A1:20:80:34BD

• Consecutive quartets of all 0s can be replaced with a double colon (::)

  • 2001:0DB8:0000:0000:0000:0000:0080:34BD -> 2001:0DB8::0080:34BD.

  • Both methods can be combined, so: 2001:0DB8::0080:34BD -> 2001:DB8::80:34BD

  • Consecutive quartets of 0s can only be abbreviated once in an IPv6 address.

    • 2001:0000:0000:0000:20A1:0000:0000:34BD -> 2001::20A1::34BD

      • How would we know how many quartets there are on each interval? We wouldn't!

      • Instead, it should be shortened like this: 2001::20A1:0:0:34BD