Today I had the need to calculate the automatically assigned IPv6 adress I knew a host probably had since the network has a router advertisment daemon.

I knew the network prefix and the hardware address (MAC/EUI-48). I suspected ipv6calc could probably do the job, but I had great trouble finding out how. I’m sure the commandline syntax for ipv6calc makes sense once you get used to it..

Anyway, here’s how, for my own and your future reference:

::

ipv6calc –in prefix+mac –action prefixmac2ipv6 2001:aaaa:bb:cccc::/64 AA:BB:CC:DD:EE:FF –out ipv6addr

IPv6 prefix as well as MAC obfuscated to protect the innocent.

Relevant links:

• [http://www.faqs.org/rfcs/rfc2373.html](http://www.faqs.org/rfcs/rfc2373.html)
• [http://packetlife.net/blog/2008/aug/04/eui-64-ipv6](http://packetlife.net/blog/2008/aug/04/eui-64-ipv6)/