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CCNP Security Secure 642-637 Quick Reference by Andrew Mason

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Chapter 3. Cisco IOS Firewall

This section covers the Cisco IOS Firewall and provides sample configurations for both the IOS Classic Firewall and IOS Zone-Based Firewall.

IOS Firewall is firewall functionality included within specific feature licenses of the Cisco IOS, which is the operating system that most Cisco devices operate. All routers, including Integrated Services Routers (ISR) run Cisco IOS. Cisco IOS has had a form of firewalling included since the early releases. This was in the form of simple packet-filtering technology. This was the first generation of firewall technology.

Packet filtering is implemented in Cisco IOS by what Cisco calls access control lists or ACLs. Nearly all Cisco routers in service have access control lists ...

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