ipfw with nat - allowing by MAC address

[Fratiman Vladut]

You need to enable layer 2 filtering if u want to block mac address,
but is not very useful because can be easy spoofed.
sysctl net.link.ether.ipfw=1
To make this change permanently edit /etc/sysctl.conf

For more information about bridge read this:
 http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/network-bridging.html
-- 
Best regards,
 Fratiman                            mailto:vladone at spaingsm.com