A packet analyzer is a tool used to capture and analyze data packets that travel over a network. It helps network administrators monitor traffic, troubleshoot issues, and ensure security by examining the contents of these packets. Commonly used in network management, packet analyzers can provide insights into network performance and detect anomalies. These tools can be hardware or software-based, with popular examples including Wireshark and tcpdump. By breaking down the data into readable formats, packet analyzers allow users to see details such as source and destination addresses, protocols used, and the data being transmitted, aiding in effective network analysis.