MAC Address

[Martijn van Oosterhout]

On Fri, Oct 18, 2002 at 08:38:12AM +0200, Michael Renzmann wrote:
> Hi.
> 
> Martijn van Oosterhout wrote:
> >I guess it's because when sending a packet, the card doesn't even look at
> >it's own MAC address. 
> 
> That is right, for SENDING. But as in wireless networks every receiption 
> of a packet from the correct destination gets acknowldeged, the card 
> looks at its own MAC address whenever a packet is received. It the 
> destination MAC corresponds with the one it is locally using, the packet 
> is destined for it and an ACK gets sent to the sender. Else the packet 
> is just thrown away.

True, but also optional. Some cards allow you to specify several MACs
addresses to match. And if you want to listen on more than that you can give
a hash bucket to match on. Not to mention promiscuous mode.

As the other person said, not allowing you to change the MAC address to
receive on would be majorly annoying in some situations. There are all
sorts of reasons to change the address. And it's not like MAC security buys
you anything.

-- 
Martijn van Oosterhout   <kleptog at svana.org>   http://svana.org/kleptog/
> There are 10 kinds of people in the world, those that can do binary
> arithmetic and those that can't.