IPFW2 Mac Address Filtering

[Elijah A.Chancey]

I've searched high and low, and have read many times that doing mac 
address filtering with ipfw is possible.

I'm running 4.9, have recompiled the kernel with 'options ipfw2', and 
have recompiled libalias & ipfw with ipfw2 support.

I've read through the man pages, and I can't make this particular rule 
work.

I need to block all IP packets EXCEPT for packets coming from specific 
MAC addresses.

Can anyone give me an example of specifically how I should form this 
rule?

Elijah Chancey
NetlinkIP Sysadmin