What is the main difference between a Network-based IDS (NIDS) and a Host-based IDS (HIDS)?

The main difference that defines the distinction between a Network-based Intrusion Detection System (NIDS) and a Host-based Intrusion Detection System (HIDS) lies in their focus and scope of monitoring. NIDS is designed to monitor and analyze traffic across the entire network. This allows it to detect potential security threats by examining data packets traveling through the network, making it effective for identifying suspicious activities that may affect multiple hosts or systems.

On the other hand, HIDS concentrates on monitoring individual hosts or endpoints. It does this by tracking system logs, file integrity, and application processes on a specific machine. This localized monitoring enables HIDS to detect intrusions that occur directly on the host device, such as unauthorized access to files or alterations to system configurations.

The correct choice highlights the key operational focus of each type of IDS, emphasizing that NIDS provides a broader view of network activity, while HIDS delivers a more granular perspective on the security state of individual devices. This distinction is essential for organizations as they strategize their security measures and decide how to effectively deploy intrusion detection systems tailored to their needs.