|Linux Networking Cookbook|
|reviewer||Dean R. Pannell|
|summary||The perfect tool when you need to be a network sysadmin but aren't|
The Linux Networking Cookbook improves on that situation in a couple of ways. First is the author herself. Carla is an experienced System Administrator and a good technical writer. She was one of the early Linuxchix, and has spent years mentoring and otherwise helping new and experienced Linux folk through their assorted dilemmas. The result is a friendly and direct, information-packed and ego-free writing style. Unlike the typical how-to that provides a list of steps that have worked for the author, Carla's discussions fill in the blanks and tell you why she takes the steps that she does.
The Cookbook is organized into an introduction followed by 18 chapters that are complete stand-alone solutions to specific problems.
The obligatory introduction is short and is not required by any of the solutions in the book, but it's worth reading. Its' eleven pages read quickly, but contain, among other things, a good explanation of the difference between bandwidth and latency and a decent overview of the whys and whens of linux-based computers as routers versus mid-range and high-end commercial routers.
Each chapter begins with an introduction of the overall topic, Routing with Linux, for example, followed by a series of short recipes organized as problem-solution-discussion. This format is convenient for diving right into work and takes advantage Carla's mentoring talents.
One problem facing any writer of Linux books is the sheer number of Linux distributions, many of which have their own distinct ways of doing things. The Linux Networking Cookbook provides solutions for both Debian and Fedora Linux. It's an excellent choice when you consider that most Linuxes derive from one of those two bases, including all of the *buntus, Knoppix, Mandriva, PCLinuxOS, CentOS, and many more. The recipes employ generic tools, which makes them easier to transport across distributions, even the SuSEs, which are based on neither Debian nor Red Hat.
For example, before obtaining The Cookbook, I needed to create a self-signed SSL certificate for a PostgreSQL server on an Ubuntu server. I'd done it a few times, but not enough to remember, so I went off to the net. The Ubuntu-themed How-To I found relied on a script called apache2-ssl-certificate. An apache script didn't bother me because I could move the pieces when I was done, or just break open the script and make it do what I wanted done. Ubuntu Feisty, however, had managed to leave the script out of the distribution, so I had to go back to the net to find an alternative approach.
Had I used The Cookboock, my task would have been simpler, though not quite as easy as it should be. Inexplicably for a book that includes network security and SSL-based VPNs, there is no entry for SSL Certificate in the index. A browse through the table of contents turns up a couple of recipes for Creating SSL-Keys for a Syslog-ng Server: one for Debian and one for Fedora. Fortunately, the Table of Contents is short and can be browsed completely in seconds, because those recipes are in the Troubleshooting Networks chapter, which is not intuitively obvious. They appear in that chapter because it contains the recipes for network monitoring, which includes installation of Syslog-ng.
The recipe itself is suitably generic, using the CA.sh script, which is part of openssl, and openssl itself to generate keys and certificates. A quick check of my Ubuntu servers, my Fedora VPS server, and my OpenSuSE workstation found CA.sh on all of them.
My OpenSuSE machine did throw one small curve:
CA.sh on my openSUSE box was located in /usr/lib/ssl/misc, as on the other boxes. However, the book tells us that CA.sh, and a moderately competent Linux user is likely to know that rpm -ql openssl will list all of the files in the openssl package or that rpm-ql openssl | grep CA.sh will spit out the location of the script.
Given the variety of Linux distributions, it is hard to imagine a better approach to take.
The Glossary of Networking Terms in Appendix B deserves special mention. Each term is explained in plain but precise language that goes beyond the cursory definitions so common in glossaries. For example, the explanation for WEP notes that it is very weak protection and urges the reader to use WPA/WPA2 instead.
Sometimes, the extra information can soften a definition's focus, but, overall, the glossary is an outstanding tool for anyone who doesn't spend his or her time knee-deep in subnet definitions, routers, and tcp dumps. The same is true of the book.
As is usual for O'Reilly, updates, errata, and scripts from the book are available on the web.
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