Port Mirroring
Port mirroring is a network monitoring technique that copies network traffic from one or more source ports on a network switch to a destination port for analysis. It allows administrators to capture and inspect packets without disrupting the normal flow of data, enabling real-time monitoring, troubleshooting, and security analysis. This is commonly implemented in switches using features like SPAN (Switched Port Analyzer) in Cisco devices or RSPAN (Remote SPAN) for remote monitoring.
Developers and network engineers should learn port mirroring when they need to monitor network traffic for debugging applications, analyzing performance issues, or detecting security threats like intrusions. It's essential in environments where packet-level inspection is required, such as in data centers, cloud infrastructure, or during network forensics, as it provides non-intrusive visibility into live traffic without affecting production systems.