Cisco IOS Cookbook, 2nd Edition

Introduction

This chapter, like the previous one, looks at system management issues on the router. But unlike the previous chapter, which looked primarily at general system administration issues such as filesystem management, here we will talk about how to manage and tune issues related to router performance, as well as deal with disaster scenarios such as creating exception dumps.

Cisco’s IOS supports a variety of special-purpose protocols and services. Some of them are useful for network management and administration, while others are more useful for testing purposes. One of the most useful of these features is the Cisco Discovery Protocol (CDP), which allows you to see useful information about the Layer 2 connections between Cisco devices. This chapter shows how to use CDP, but it also discusses some of the well known security problems with the protocol. It is best to simply disable this service.

Disabling is often the best strategy for several of the other services. Some, like the HTTP management interface and the various test protocols lumped together under the title of the TCP and UDP small servers, serve no real purpose in most production networks, so they are disabled by default. But others, like DNS, do have useful functions, and are enabled by default.

We will discuss several important administrative features, such as different methods for handling the hostnames of other network devices and command aliases that make complex commands easier to remember and type. The chapter ...