What is a primary function of an Intrusion Detection System (IDS)?

A primary function of an Intrusion Detection System (IDS) is to detect and alert on suspicious activities within a network or system. IDS systems monitor traffic patterns and analyze packet data for unusual behavior that may indicate potential security breaches or attacks. When such activities are detected, the IDS generates alerts to inform administrators, allowing them to investigate and respond accordingly. Unlike intrusion prevention systems (IPS), which actively block attacks, IDS focuses on monitoring and detection; its role is crucial in enhancing an organization's ability to identify and manage security incidents effectively.

The other options pertain to different security functions. For instance, preventing all attacks is beyond the operational scope of an IDS, as it solely detects rather than prevents them. Blocking unauthorized access is typically a function associated with firewalls or perimeter security tools, which actively deny access based on established security rules. Network address translation is a technique used to modify network address information in IP packet headers while in transit, which does not relate to the detection of intrusions or suspicious activities.