Which of the following best describes the function of port mirroring in an IDS?

Port mirroring is a technique commonly used in networking for monitoring and analysis purposes, especially in Intrusion Detection Systems (IDS). The function of port mirroring involves replicating a stream of network traffic and sending this duplicate copy to a designated monitoring device, such as an IDS. This allows the IDS to inspect the traffic in real-time without interrupting or altering the flow of data on the network.

By creating a duplicate of the traffic, the IDS can analyze packets for signs of suspicious activity, potential threats, or policy violations without being part of the data path, maintaining the integrity and performance of the network. This passive monitoring is crucial for security teams to detect intrusions and respond appropriately.

Other options describe functions that are not aligned with the purpose of port mirroring. For instance, the idea of modifying traffic contradicts the passive role of an IDS, which solely observes and reports without influencing the actual data being transmitted. Blocking incoming traffic introduces an active interception that goes beyond monitoring, while enhancing network performance does not relate to the core function of traffic observation through port mirroring. The focus here is on monitoring and analysis rather than direct interference with network operations.