Which device monitors network traffic across a network rather than a single host?

Which device monitors network traffic across a network rather than a single host?

• A. Web Application Firewall (WAF)
• B. Host-Based IDS (HIDS)
• C. Network-Based IDS (NIDS)
• D. API Gateway

Answer: (C)

Monitoring traffic across a network means watching data as it moves between devices, not just on one machine. A Network-Based IDS is built for that broad visibility: it places sensors at key points in the network to capture and analyze packets traversing multiple segments. This lets it detect unusual or unauthorized activity that could affect any device on the network, rather than focusing on a single host.

In contrast, a Host-Based IDS is tied to one machine and only monitors activity on that specific host, offering limited view of the overall network. A Web Application Firewall protects a web application by filtering HTTP/S traffic at the application layer, usually at the edge of a web server. An API Gateway handles API requests and security for APIs but isn’t primarily a network-wide traffic monitor.