Definition
Tcpdump is a powerful command-line utility used for capturing and analyzing network traffic in real time. It works by listening to network interfaces and saving packets that match specified filter criteria to a file or displaying them directly on the console. Understanding tcpdump is crucial for network troubleshooting, security monitoring, and performance analysis. For instance, a security analyst might use tcpdump to identify suspicious outbound connections from a compromised host. Unlike more user-friendly graphical tools like Wireshark, tcpdump requires familiarity with command-line syntax and packet structure. This tool is frequently encountered in cybersecurity certifications such as CompTIA Security+ and CySA+.