In the SAFE small network implementation, we will look at the specific configuration requirements for the following components:
Internet service provider (ISP) router
Cisco IOS Firewall router
PIX Firewall
These three components are the major networked devices that can be used within the small network. Technically, the ISP router is not part of the small network design, but because it plays a major role in the overall design aspects, it is included here for completeness. Also, the functionality of the ISP router can be integrated in some circumstances within the Cisco IOS Firewall router, thus eliminating it from the design.
Chapter 13, Figure 14-1 illustrates the small network modules and their respective devices.
General configuration guidelines on effective tightening of security on Cisco routers and switches are listed in Appendix B, "General Configuration Guidelines for Cisco Router and Switch Security." Readers should familiarize themselves with the content of this appendix because these commands are not shown in the following sections but play an important role in the overall implementation.