Santos:CCNA Sec 210-260 OCG

Firewall Technologies

We know that a firewall has a goal of separating two entities, and specifically controlling access between those two, such as two networks. Most commercial firewalls today can do packet filtering, application layer inspection, stateful packet filtering, NAT (in all its flavors), AAA functions, and perform virtual private network (VPN) services. A good example of a device such as this is the Cisco Adaptive Security Appliance (ASA), which is a dedicated firewall appliance. Many of these same features can all be implemented in software and on top of an IOS router whose license, memory, and CPU can support it. A dedicated firewall appliance is considered more secure and therefore preferable to simply using a standalone router. ...