* Tool
Tcpdump

* Link
https://www.tcpdump.org/
https://www.tcpdump.org/manpages/tcpdump.1.html

* Description
Tcpdump prints out a description of the contents of packets on a network interface that match the Boolean expression; the description is preceded by a time stamp, printed, by default, as hours, minutes, seconds, and fractions of a second since midnight.
Within the VARIoT project, tcpdump captures into a pcap file all network traffic between the laboratory and the Internet.

* Usage
Command line options:

root@host:~# tcpdump -i interface -w /path/to/output.pcap -s0 -v

-i interface => interface to listen
-w /path/to/output.pcap => output pcap file
-s0 => default packet snapshot length, 262144 bytes
-v => When parsing and printing, produce (slightly more) verbose output.

* Output
pcap file.

