Which of the following would allow you to automatically close connections or restart a server or service when a DoS attack is detected?

An Active IDS - also referred to as an Intrusion Prevention System (IPS) - takes automated preventive action when an attack such as a DoS is detected. These actions include terminating malicious TCP sessions, blocking offending source addresses, or restarting affected services, providing real-time mitigation rather than alerting alone.

A Passive IDS only monitors traffic and generates alerts when an attack is detected; it cannot automatically terminate connections or restart services.

Network-based IDS (NIDS) describes sensor placement on the network segment, not the system's response capability - a NIDS can be either active or passive.

Signature-based IDS refers to the detection method of matching known attack patterns, not the response capability, and does not inherently provide automated remediation.