how to find out promiscuous mode

[Gilboa Davara]

On Thu, 2010-02-04 at 11:17 +0000, Alan Cox wrote:
> On Thu, 04 Feb 2010 09:06:27 +0200
> Gilboa Davara <gilboad at gmail.com> wrote:
> 
> > On Wed, 2010-02-03 at 23:11 +0100, Vadkan Jozsef wrote:
> > > How can I find out that someone is using it's network card in
> > > promiscuous mode in a subnet?
> > > 
> > > Thank you!
> > > 
> > 
> > You can't.
> > ... and even if you could, someone could potentially use a passive
> > splitter and yank all the packets of the subnet.
> > 
> > Having said all that, if your network is switched (as opposed to using
> > cheap FE hubs), only broadcast traffic (ARP/DHCP/etc) will be visible in
> > promisc mode.
> 
> Which won't save you against a smart attacker unless you are keeping
> an eye on the traffic on the network.
> 
> If I want to listed to IP traffic between A and B I can spoof ARP
> frames in both directions, the switch will ensure neither box sees the
> unicast arps being used to poison the other and I can then forward the
> frames with the mac headers faked.
> 
> Alan

I'm well aware of that.
Please read my second comment.

- Gilboa