The Cisco Secure Intrusion Detection System (formerly NetRanger), is an enterprise-scale, real-time, intrusion detection system designed to detect, report, and terminate unauthorized activity throughout a network. The industry's first intrusion detection system, The Cisco Secure Intrusion Detection System is the dynamic security component of Cisco's end-to-end security product line.The Sensor is a network appliance that combines high reliability with installation and maintenance simplicity. Each network segment monitored requires a dedicated Sensor, including the Internet, intranets, and extranets. The Sensor appliance is optimized for specific data rates and interfaces, such as Ethernet (10BaseT), Fast Ethernet (100BaseT), Token Ring (4 and 16 Mbps), and Fiber Distributed Data Interface (FDDI) (Single or Dual mode). It uses an expert rules-based system engine to distill large volumes of IP network traffic into meaningful security events. It features a unique "three-tiered" attack detection capability to pinpoint unauthorized activity, including, Named attacks, General Category attacks, and Extraordinary attacks. The Sensor can also monitor a router's syslogs for security policy violations, log the security data, "kill" active TCP sessions, and dynamically manage a router's access control lists to shun intruders.