TCPDump is a command-line packet analyzer tool used for network troubleshooting and analysis. It captures and displays the data packets transmitted over a network, allowing users to monitor network traffic in real-time. This tool is widely used by network administrators and security professionals to diagnose issues and understand network behavior. The captured data can be filtered based on various criteria, such as IP addresses, protocols, and ports, making it easier to focus on specific traffic. TCPDump is available on various operating systems, including Linux and macOS, and is often used in conjunction with other network analysis tools for comprehensive monitoring.