LinuxTechi - https://www.linuxtechi.com/install-use-wireshark-debian-9-ubuntu/
Wireshark is free and open source, cross platform, GUI based Network packet analyzer that is available for Linux, Windows, MacOS, Solaris etc. It captures network packets in real time & presents them in human readable format. Wireshark allows us to monitor the network packets up to microscopic level. Wireshark also has a command line utility called ‘tshark‘ that performs the same functions as Wireshark but through terminal & not through GUI.
Wireshark can be used for network troubleshooting, analyzing, software & communication protocol development & also for education purposed. Wireshark uses a library called ‘pcap‘ for capturing the network