An Intrusion Detection System (IDS) is a type of security software that monitors network traffic and system activity for signs of malicious activity or policy violations. It works by analyzing events and data from various sources, including network traffic, system logs, and application activity, to detect potential security threats. Once a potential threat is detected, the IDS can alert security personnel or take automated action to block or mitigate the threat. IDS can be either network-based, which monitors network traffic, or host-based, which monitors activity on a specific computer or system. IDS is an important component of modern cybersecurity and can help organizations detect and respond to security incidents before they cause significant damage.