IDS stands for Intrusion Detection System. It is a security technology that monitors network traffic or system activity for malicious behavior or policy violations. The main objective of an IDS is to detect potential security incidents and alert security administrators or security operation center (SOC) personnel so they can take action to prevent or mitigate the impact of an attack.

There are two types of IDS: network-based IDS (NIDS) and host-based IDS (HIDS). NIDS monitors network traffic for suspicious activity such as network scans, port scans, and attempts to exploit vulnerabilities in network services. HIDS, on the other hand, monitors system activity on individual hosts, such as logins, file accesses, and system configuration changes.

IDS can be rule-based or behavior-based. Rule-based IDS uses pre-defined rules to detect known threats or policy violations. Behavior-based IDS, also known as anomaly detection, uses machine learning algorithms to analyze network or system behavior to detect abnormal activity that may indicate a security incident.

IDS is an important component of a comprehensive security strategy and is often used in conjunction with other security technologies such as firewalls, antivirus software, and security information and event management (SIEM) systems.