Quote Originally Posted by aay
Is it possible then to have all ports forwarded to a non existant address (even ones you want to access) unless your incomming request meets certain requirements: for example, having a specific mac address? That would be really nice.
You should be able to do something like that using

--mac-source [!] address
Match source MAC address. It must be of the form
XX:XX:XX:XX:XX:XX. Note that this only makes sense for packetscoming from an Ethernet device and entering the PREROUTING, FORWARD or INPUT chains.

found this in
man iptables