How to make ipfw consider MAC-IP match?

[Artem Kuchin]

Hi!

I have a table with ethernet (MAC) addresses matching IPs. It is
used to build dhcp config file. But regardless of that any user can
assign his neighbour ips while that pc is turned off and use it to
access internet. The local ips are 192.168. and are behind natd.
I am running 5.3-STABLE and have heard that ipfw2 can in someway
use MAC addresses, but how do I setup ipfw in such a way that
it allows certain IP only from one and only one MAC address?
I hope you are getting my idea.

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Regards,
Artem Kuchin