A firewall is a network security system that processes data packets coming into and going out of a network according to predefined rules based on IP address and port number. Adaptive Security Appliance is what Cisco's firewall is officially known as ASA. The performance levels of the Cisco ASA Firewalls can be customized to fit your network and your budget, and they offer the same tried-and-true level of security that safeguards some of the largest networks at some of the most security-conscious businesses in the world.All Rights Reserved