Which Intrusion Detection System is best applicable for large environments where critical assets on the network need extra security and is ideal for observing sensitive network segments?

NIDS sensors are placed at key network positions such as behind firewalls or on core switches, allowing passive analysis of all traffic traversing a segment without requiring agents on individual hosts. This architecture scales efficiently across large environments and is uniquely suited to observing sensitive network segments because it can detect attacks targeting any device on those segments simultaneously.

Host-based IDS is installed directly on individual endpoints and only monitors activity on that single host, providing no visibility into network-level threats affecting other systems in a large environment.

Firewalls enforce access control by permitting or blocking traffic based on defined rules but do not perform behavioral or signature-based analysis to detect intrusions - they are a prevention mechanism, not an intrusion detection system.

Honeypots are decoy systems designed to lure and observe attackers in a controlled environment, not to monitor and protect production network segments across a large-scale infrastructure.