RE: Effects of promiscuous mode
On 14-Sep-2001 Rino Mardo wrote:
> hi. a friend of mine asked but i couldn't give a definite, not even
> an, answer so i was hoping someone here can shed a light:
>
> "I'm checking out snort, a network intrusion detection system. I
> noticed that when I start the snort daemon to listen on eth0 (my NIC
> connected to the Internet), the interface enters promiscuous mode. I know
> what promiscuous mode is, but I'm wondering what the impacts of the
> device's being on promiscuous mode will be.
>
The NIC will be working a little more because it reacts to every packet on the
wire, even ones it would usually not be interested in. This will likely mean a
little more OS/CPU work as well.
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