(Wireshark (formerly ethereal) is a network packet analysis software. The function of network packet analysis software is to capture network packets and display the most detailed network packet data as far as possible. Wireshark uses WinPcap as the interface to exchange data packets directly with the network card. In the past, network packet analysis software was either very expensive or specifically for profit. The emergence of ethereal changed all this. Within the protection scope of GNU GPL general license, users can obtain the software and its source code for free, and have the right to modify and customize its source code. Ethereal is one of the most extensive network packet analysis software in the world.)