Which of the following intrusion detection systems (IDS) monitors network traffic and compares it against an established baseline?

File-based IDS (also known as Host-based IDS or HIDS) primarily monitors system files, logs, and processes on a host, not network traffic against a baseline.

Network-based IDS (NIDS) is a category that monitors network traffic, but it can be either anomaly-based or signature-based; it's not the specific method of comparing against a baseline.

Anomaly-based IDS builds a baseline profile of normal network activity, including traffic patterns, bandwidth usage, and protocol behavior. Any deviation from this established baseline is flagged as an anomaly, potentially indicating an intrusion or malicious activity.

Signature-based IDS detects intrusions by comparing network traffic patterns against a database of known attack signatures, not against an established baseline of normal activity.