ipv6

Convert from a MAC address to an IPv6 address

I would like to understand how to convert a MAC address to an IPv6 address.

For example,

00:01:04:76:2A:5C

Should become

FE80::0201:04FF:FE76:2A5C

How can I do the conversion? We suppose an automatic configuration without a random parameter for a local machine.

Solution

  • Conversion step by step from a MAC address (48 bits) to a IPv6 address (128 bits):

    1. take the mac address: 52:74:f2:b1:a8:7f
    2. throw ff:fe in the middle: 52:74:f2:ff:fe:b1:a8:7f
    3. reformat to IPv6 notation 5274:f2ff:feb1:a87f
    4. convert the first octet from hexadecimal to binary: 52 -> 01010010
    5. invert the bit at index 6 (counting from 0): 01010010 -> 01010000
    6. convert octet back to hexadecimal: 01010000 -> 50
    7. replace first octet with newly calculated one: 5074:f2ff:feb1:a87f
    8. prepend the link-local prefix: fe80::5074:f2ff:feb1:a87f