How the Promiscuous Mode Scanner Tool works
This tool actively scans your subnet with modified ARP packets
and shows the devices responding to each type of ARP packets.
The devices that respond to nearly every packet are most likely
listening in Promiscuous Mode (ie. the ethernet interface is
capturing IP packets not intended for that IP address). All IPv4
devices MUST respond to ARP even if they are running a firewall
and invisible to normal ICMP Ping. Note that ARP is not routed
so you are limited to your subnet.
The image below shows a DSL router in the first row listening in
Promiscuous Mode which would be expected from this type of device.
Note that the scanner requires the use of WinPcap. We install
WinPcap as part of the installation package. WinPcap is designed
for wired ethernet cards, not cellular modems and it usually works
well with 802.11x wireless interfaces.