Wireshark is a widely used network protocol analyzer that helps in capturing and interactively browsing the traffic on a network. It is an essential tool for incident responders like Eric who are developing incident-handling plans and procedures. By analyzing network traffic, Wireshark allows users to see what is happening on their network at a microscopic level, making it invaluable for troubleshooting network problems, analyzing security incidents, and understanding network behavior. Whois is used for querying databases that store registered users or assignees of an Internet resource. Burp Suite is a tool for testing web application security, and FaceNiff is used for session hijacking within a WiFi network, which makes Wireshark the best choice for analyzing network traffic.