Kevin Dooley - Cisco IOS Cookbook

Copyright 2008 O'Reilly Media, Inc.

The first important difference between the first and second editions of this book is visible right on the cover: we changed the title from Cisco Cookbook to Cisco IOS Cookbook . We had two main reasons for making this change. First, its more accurate. Cisco has several different product lines with completely different configuration interfaces. This book just covers the Cisco Internetwork Operating System (IOS), the software that runs on most of Ciscos routers and switches. It doesnt cover PIX or ASA firewall configuration or content switching or Ciscos Intrusion Detection Systems (IDS), for example.

The second reason for the change is that somebody might one day want to write a Cisco firewall or content switching or IDS cookbook. In fact, several readers have written to us asking for such things, although having just completed the marathon process of updating this book, neither of us feels a burning desire to undertake such a project right away.

For the second edition, we had two main goals. The first was to update the information for the first edition so that it now reflects IOS Version 12.4. And our second goal was to add some of the new topics, like MPLS and IPv6, which have become more relevant since the first edition was published. Many of these ideas came from reader suggestions. However, Cisco rarely deletes features from its software when it creates a new version, so we have also retained most of the content from the first edition of this book.

This means that much of the content in this book is also relevant to lower IOS versions. We have tried to make it clear when certain features were introduced, or if they are only available with certain IOS feature sets.

In each chapter, whenever there were relevant and useful new features, we have added new recipes showing how to use these features effectively. And when there were modifications to existing features, we have added information to the existing recipes.

We have also written four new chapters on topics that either were requested by readers, or that we felt were interesting and important. The new chapters cover IP Mobility, IP Version 6, MPLS, and Security, respectively.

In all, this edition contains 89 entirely new recipes, and we have deleted two old ones, one because we didnt feel it was still the best solution to the problem, and the other because it made sense to absorb its content into another recipe. We have made significant updates to existing recipes in every chapter, mostly to describe useful new options to existing commands.

We welcome feedback from our readers. If you have comments, suggestions, or ideas for other recipes or topics that youd like to see covered, please let us know. Just as we did with this edition, if there are additional future editions of the Cisco IOS Cookbook , we will include any suggestions that we think are especially useful. You can reach us at or ijbrown@hotmail.com .

As the name suggests, the Cisco Cookbook is organized as a series of recipes. Each recipe begins with a problem statement that describes a common situation that you might be faced with. After each problem statement is a brief solution that shows a sample router configuration or a script that you can use to resolve this particular problem. Then we turn to a discussion section where we describe the solution, how it works, and when you should or should not use it.

We have tried to construct the recipes so you can turn directly to the one that addresses your specific problem and find a useful solution without needing to read the entire book. If the solution includes terms or concepts that you are not familiar with, the chapter introductions should help to bridge the gap. And many recipes refer to other recipes or chapters that discuss related topics. We have also included a variety of references to other sources in case you need more background information on a particular subject.

The chapters are organized by the feature or protocol discussed. So, if you are looking for information on a particular feature such as NAT, NTP, or SNMP, you can turn to that chapter and find a variety of related recipes. Most of the chapters list the more basic problems first, and any unusual or complicated situations last. But there are some exceptions to this, when we have opted instead to group related recipes together.