server, misc, security

IPv6 Cheatsheet

IPv6 128 Bits vs IPv4 32 Bits

IPv6 Addresses are broken down into 8 groups of 4 digits (16 bits), separated by colons.

Shortening:

  • :: - Double Colon Rule

    • Once per address
    • Remove all consecutive zeros
    • Example:
      • 0000:0000:0000:0000:0000:0000:0000:0001 -> ::0001
      • 2001:0D88:1111:0001:0000:0000:0000:0003 -> 2001:0D88:1111:0001::0003

  • Leading Zero Rule

    • Omit leading zeros in every group
    • Example:
      • 0000:0000:0000:0000:0000:0000:0000:0001 -> ::1
      • 2001:0D88:1111:0001:0000:0000:0000:0003 -> 2001::D88:1111::1::3

HowTo Determine Network and Subnet:

Prefix Length is an integer between 1-128 and defines how many bits of the address are representing the network and subnet.
PL / 4 = Number of bits

  • Example:
  • 2001::D88:1111::1::3/64
  • 2001:0D88:1111:0001:0003/64

64 / 4 = 16 = 2001:0D88:1111:0001::/64