Deploying Zone-Based Firewalls

Chapter 1. Introduction to Zone-Based Firewalls

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• Simple Zone-Based Design 4

• More Complex Zone-Based Design 5

• Implementing Zone-Based Designs 7

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In the mid-1990s, when the large corporate networks began to be connected to less-secure public networks (for example, the early Internet), security-conscious network administrators immediately started to feel the need to secure their internal networks from potential intruders. Networking vendors immediately responded with various filtering mechanisms, most commonly implemented as packet filters (filters that could accept or deny incoming or outgoing packets based on their addresses, transport protocol, or port numbers). The initial implementations of what we call firewalls ...