Wireshark is an open-source network protocol analyzer that allows users to see what is happening on their network at a microscopic level. It can capture and display packets from a wide range of protocols and allows for detailed filtering and analysis of network traffic. The software also includes advanced features such as VoIP analysis and decryption of SSL/TLS traffic. Overall, Wireshark is a powerful tool for network administrators and security professionals to troubleshoot and analyze network traffic.