Network interface: device connecting a computer
to a network, such as an Ethernet or WiFi card.
– A computer may have multiple network interfaces.
– Most local area networks, including Ethernet and
WiFi, broadcast frames, so all hosts on the LAN
receive them.
– In regular mode, each network interface sends only
packets destined for it to OS for processing.
– Network sniffing can be accomplished by configuring
the network interface to send all frames
(promiscuous mode) to OS for processing.