What is the purpose of intrusion detection systems (IDS)?

Intrusion detection systems (IDS) are designed specifically to monitor network traffic for suspicious activity and potential threats. Their primary purpose is to detect unauthorized access or anomalies that could indicate a security breach, which allows organizations to respond quickly to potential threats. An IDS examines both inbound and outbound traffic, using various detection methods such as signature-based detection, which looks for known threats, and anomaly-based detection, which identifies abnormal behavior within the network.

The functions of IDS are critical for maintaining the security posture of a network, as they provide real-time alerts that can help security teams investigate incidents and take appropriate action to mitigate risks. By focusing on monitoring rather than blocking, an IDS plays a complementary role alongside other security measures, such as firewalls and authentication systems. This distinction clarifies why the other options, related to encryption, firewall protection, and user authentication, do not accurately describe the core purpose of an IDS.