Re: mac filtering

[Marek Kierdelewicz <marek@piasta.pl>]

Hi,

> 
>I have a client machine (say A ) connectected to a linux router . I
>can browse internet without any problem .
>In router , i can configure  MAC address filters . If i configure A's
>mac address should be disabled , A cannot access Router itself ? .
>Question : What exactly mac address filter mean ?  disabling router
>access or disabling internet access ?

If you add following rule you'll block access to internet, not to
router:
iptables -A FORWARD -j DROP -m mac --mac --mac-source xx:xx:xx:xx:xx:xx

This rule will block access to the router without affecting access to
internet:
iptables -A INPUT -j DROP -m mac --mac --mac-source xx:xx:xx:xx:xx:xx

You can find nice diagram representing packet flow in netfilter here
(focus on green background if you're only routing, not bridgeing):
http://www.imagestream.com/~josh/PacketFlow.gif

Best regards,
Marek