Introduction

It is a clich , but a true one, to say that network security is vital and integral to any organization needing to protect its information. Good security administration can be labor-intensive, and organizations can find it difficult to maintain the security of a large number of internal machines. Most organizations place a layer of security in the form of a firewall between the networks containing their data and the users (trusted and untrusted) of that data. Increasingly, firewalls provide additional security or performance services; they sit at a point in the network that mediates all communication with the end host, so various types of service extensions can naturally be integrated into them.

Even in high-security environments, where the resources to harden and provide ongoing security support for the end application are available, firewalls can play an important role. Firewalls can help provide defense in depth: multiple protective technologies support higher levels of trust in case of error or omission at one layer. Having multiple controls also supports the concept of separation of duties: different groups can support application layer and network layer securities, ensuring that no single person or group can compromise the entire system.

Cisco PIX firewalls are a line of appliances that offer world-class security and high levels of performance and reliability. They are a mature product, having been a part of enterprise and service provider networks since 1995. Cisco PIX firewalls fit into a wide range of environments, from small office/home office (SOHO) environments to large...