Chapter 4. Cisco IOS Firewall Configuration
The Cisco IOS Firewall provides a full-featured firewall solution for customers that do not want (usually because of financial constraints) to deploy a firewall appliance. Before diving into the features in Cisco IOS, however, it's important to understand the types of firewalls available, the reason we have firewalls, and the way they have evolved.
Firewalls in themselves are a simple concept. A firewall is designed to limit the damage that can happen between subnets in the event of an outbreak. This is similar to firewalls in cars, homes, and office buildings. Much of it is all about containment. We might not be able to prevent the outbreak, but with a firewall you can contain ...