Several tools exist that can monitor network traffic, usually such tools will put the network card
of a computer into promiscuous mode, this enables the computer to listen to the entire traffic on
that section of the network. Filtering of this packets can be done based on the IP related header
data present in the packets, usually such filtering specifies simple criteria for the IP addresses and
ports present in the packets. These passive network sniffing programs have been developed for
either wired or wireless network measurement; the best-known are tcpdump and Wireshark.