This book assumes you have some experience with Linux. While it does not require that you have a network of Linux computers, you can take full advantage of the techniques described in this book only if you have such a network.
Some of the tools described in this book require a subscription. For example, access to the Red Hat Network Proxy Server requires a specialized subscription to the Red Hat Network. Access to SUSE Linux Enterprise Server updates requires subscription access to the YaST Online Update Server. Access to Novell's Zenworks Linux Management also requires a subscription. If you want to try out these tools, navigate to the associated Web sites. Trial subscriptions may still be available. And read this book!
Some of the tools described in this book are freely available. They are already included with many Linux distributions. Some have been customized by third parties for popular distributions, such as Red Hat Enterprise Linux. They are designed and maintained by the Linux community and are available courtesy of the GNU General Public License (http://www.gnu.org/copyleft/gpl.html).