Wireshark is a packet-sniffing application that is used by IT professionals for a diverse set of requirements (including forensics, troubleshooting, and enhancing network performance). You can download it for free from https://www.wireshark.org/download.html, where it is available for the majority of platforms, including Linux, Macintosh, and Windows.
Packet sniffing is also referred to as tapping into the wire, which basically involves reading pieces of information traveling in a communication channel. Considerations such as placement of sniffer, protocols to be analyzed, and communication channel type need to be assessed before capturing network packets.
