Get MAC from DUID

[sthaug at nethelp.no]

> I would like to suggest that you turn to address tracking to find this
> information. IPv6 provides the MAC address for every 'neighbor' in a
> manner similar to the IPv4 ARP table.. Explicitly ask the devices (maybe
> the router, maybe the DHCP server) on the wire with host for the
> neighbor relationship. With vendor 'C', it is 'show ipv6 neighbor [ipv6
> address]', With Unix, 'ip -f inet6 neigh',

Minor update here: I believe 'ip -f inet6 neigh' is Linux-spesific. It
certainly doesn't work for FreeBSD, where the corresponding command is
'ndp -a'.

Aside from that, there has been quite a bit of discussion about how to
obtain the MAC address in connection with DHCPv6 on this list. See for
instance the "host-identifier with IPv6" thread starting at

    https://lists.isc.org/pipermail/dhcp-users/2009-February/008088.html

and  "DHCPv6 host-identifier, the Never Ending Thread: A Summary" at

    https://lists.isc.org/pipermail/dhcp-users/2009-March/008307.html

Steinar Haug, Nethelp consulting, sthaug at nethelp.no