What is an intrusion detection system (IDS)?

An intrusion detection system (IDS) plays a crucial role in network security by monitoring both network traffic and system activities. It functions by analyzing incoming and outgoing data packets, along with system logs, to identify patterns or behaviors that may indicate malicious activities or policy violations. When the IDS detects suspicious activity, it generates alerts for network administrators, enabling them to respond promptly to potential threats.

This choice aligns with the primary function of an IDS, which is to act as a surveillance mechanism for identifying and reporting on potential security breaches. Unlike firewalls, which primarily prevent unauthorized access to and from a network, an IDS focuses specifically on identifying intrusions as they occur, providing insights into what is happening within the network environment.

In summary, the correct answer emphasizes the monitoring aspect and proactive alerting provided by an IDS, which is integral to maintaining the security posture of an organization.