Formerly known as the PIX Firewall, the Cisco Secure PIX Firewall series delivers strong security in an easy-to-install, integrated hardware/software appliance that offers outstanding performance. The series allows you to rigorously protect your internal network from the outside world - -providing full firewall security protection. Unlike typical CPU-intensive full-time proxy servers that perform extensive processing on each data packet at the application level, Cisco Secure PIX firewalls use a non-UNIX, secure, real-time, embedded system. The PIX Firewalls deliver superior performance of up to 256, 000 simultaneous connections, over 6, 500 connections per second, and nearly 170 megabits per second (Mbps) throughput. This level of performance is dramatically greater than that delivered by other appliance-like firewalls or those based on general-purpose operating systems.This is a PIX 520 Firewall with extra memory - Max 6 interfaces, 350-MHz processor, 170-Mbps performance, 128 MB memory, four expansion slots.