What is the primary function of an intrusion detection system (IDS)?

The primary function of an intrusion detection system (IDS) is to detect unauthorized access or anomalies in network traffic. An IDS continuously monitors network systems, analyzing the traffic for signs of potential security breaches or malicious activities. It serves as a critical component in a security infrastructure by identifying suspicious behavior that may indicate intrusions or attacks, such as unauthorized access attempts, unusual data transfers, or the presence of known malware signatures.

The strength of an IDS lies in its ability to recognize deviations from normal network behavior, allowing administrators to investigate and respond to threats promptly. While it may provide alerts and log potential incidents for further analysis, it does not actively block or prevent these intrusions; that is the role of intrusion prevention systems (IPS).

The options that mention monitoring employee internet usage and backing up critical database information do not align with the primary purpose of an IDS. Prevention of unauthorized access relates more closely to security measures like firewalls and intrusion prevention systems rather than detection systems. Therefore, the correct choice accurately reflects the main goal of an IDS in network security.