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I like this book and at the same time I found it hard to read for very long at a time. I'll give my hypotheses later. First, why I like it. I have been using Linux for four years. It is what I have wanted since I first encountered Unix twenty-five years ago, a Unix system I could afford. Now I have it -- a true multi-user, multi-tasking OS with good logging. Power and visibility. My systems are already working well. This book is about improving a good thing.
This is a HOWTO book for system/network administration. It covers only software -- kernel build options, routing (both static and dynamic), firewalls, and infra-structure servers (as opposed to application servers like an e-commerce system). There are font servers, shared file servers, Web servers, backup servers, and more. Also remote system administration via SSH, exported X Windows applications, Virtual Network Computing (VNC), and the Web. There is a section on Virtual Private Networks (VPNs, see quote below). For details, see the Table of Contents on the author's Web site at http://www.rodsbooks.com/adv-net/. There is enough coverage to get things up and running smoothly, but it won't replace the reference books dedicated to a single program. For example, O'Reilly's book on Sendmail and the SAMS book on Postfix are each larger than this book and it gives one chapter to both programs plus Exim. However, you are unlikely to need the reference book for all the covered servers. Wading in is often easier and more productive than jumping directly into the deep end. The coverage is usually enough to get a feel for the effort needed to install or migrate between alternatives. Sometimes the default choice in a distribution is not the best choice for a particular situation.
This summary for the VPN chapter is representative of Smith's style:
A VPN is a useful tool for extending the reach of a local network. You can use this tool to give individual remote users, or entire remote networks, access to nonpublic servers on your local network. This is an extremely useful tool when you want to support telecommuting or when you want to tie together two or more networks at distant locations, in order to share servers or otherwise integrate those networks. Several VPN products exist, and many of these are available for Linux. Two particularly popular protocols are PPTP, which is implemented in Linux by PoPToP and PPTP-Linux, and FreeS/WAN. PPTP is commonly used by individual remote clients to link to a central network, while FreeS/WAN is more commonly used to tie together entire networks. Both can be used either way, though. Before you implement a VPN, you should carefully consider the security implications of doing so, paying particular attention to the fact that each VPN client is another potential entry point to your local network.
I read a lot of books. The good ones I review. My method is to mark interesting pages with stickies: green for to do items, blue for possible quotes, yellow for items mistakes to check, and red for typos and errors. When I finished this book, there was only one red sticky and no yellow stickies. For a book this size and depth, six to eight red stickies is typical. Now I read books to learn something, not because I know it all, so there are undoubtedly other mistakes. But still, one red sticky is remarkable. (It is interesting and humbling to check the errata afterwards. I usually catch 1/10 to 1/4 of the errors.)
There were thirty green stickies. That is a lot of neat stuff to try out plus tips and tweaks. This is probably the most green stickies of any book I have read. That is a lot of useful information.
There were only two blue stickies. Smith is a very good, factual writer with a wealth of knowledge and experience. But he isn't a particularly quotable writer. It is the information and experience that dazzles, not the writing.
One of Linux's strength is choice - the many distributions (hundreds at last count) and myriad programs that solve the same problem (e.g., mail readers). This diversity is reflected well in the book. He covers most of the major distributions: Caldera, Debian, Mandrake, Red Hat, Slackware, SuSE, and TurboLinux (all circa early 2002). He also covers several solutions for most problems (e.g., inetd and xinetd). He often identifies which program is each distributions's default and covers how it is configured in that distribution. This broad coverage is good for intermediate to advanced Linux users.
There is a refreshing lack of attitude. The one possible exception is qmail. Smith admits that it is possibly the second most commonly used Linux mail server, but since none of the distributions covered ship with qmail as the default, he doesn't cover it.
At some point, I began to wonder where did he learn all this stuff? He is writing more than a book a year! I see three possibilities. Cleary he concentrates on just one area, Linux systems/network administration. He is writing books in parallel and may reuse text or ideas. (The preface mentions SuSE 7.3 and the mail server section mentions SuSE 7.1, versions that are about a year apart.) The last point is a bit petty, but reflects the realities of being a professional writer. Blaise Pascal once apologized that his letter was longer because he did not have time to make it shorter.* Smith's writing is more verbose than most technical writers. This can be a strength as well as a weakness. Personally, I prefer the more terse style, but the section on Postfix covered one point better than both the Postfix program docs and the "Postfix" book. I previously had dug into the source code to understand it, but not everyone has that option. It was nice to see my understanding confirmed by another. In writing, like almost any endeavor, you have to balance time to complete with relevance and the need to put food on the table.
Where does this book fit into a Linux guru aspirant's education? Clearly it comes after the "Learning Linux in Commercial Breaks for the Newbie" type books. I suggest it also comes after a shorter networking book like "Linux Network Administrator's Guide". It does fit in before the dedicated, reference books on single programs. One place it fits is after you have volunteered to set up and administer the network for your high-tech, low-rent startup and before you actually do it.
This book is going to stay on my desk for several months as I work through the green "to do" stickies in my spare moments. It will stay within reach for several years. In spite of my lack of enthusiasm for his writing style, I like it and recommend it to fellow travelers on the path to Linux guru-hood.
-- Jeffrey Taylor (jeff.taylor@ieee.org)
* Editor's note: This quotation, or some variation, has also been attributed to Voltaire, Abraham Lincoln, and Chekhov, among others. But the Oxford Dictionary of Quotations credits it to Blaise Pascal. "Je n'ai fait celle-ci plus longue que parce que je n'ai pas eu le loisir de la faire plus courte." and translates it as: "I have made this [letter] longer than usual, only because I have not the time to make it shorter." --Lettres Provinciales (1657) no. 16.
Part I Low-Level Configuration
1 Kernel Network Configuration
2 TCP/IP Network Configuration
3 Alternative Network Stacks
Part II Local Network Servers
5 Configuring Other Computers via DHCP
6 Authenticating Users via Kerberos
7 File and Printer Sharing via Samba
8 File Sharing via NFS
9 Printer Sharing via LPD
10 Maintaining Consistent Time: Time Servers
11 Pull Mail Protocols: POP and IMAP
12 Running a News Server
13 Maintaining Remote Login Servers
14 Handling GUI Access with X and VNC Servers
15 Providing Consistent Fonts with Font Servers
16 Maintaining a System Remotely
17 Performing Network Backups
Part III Internet Servers
18 Administering a Domain via DNS
19 Push Mail Protocol: SMTP
20 Running Web Servers
21 Running FTP Servers
Part IV Network Security and Router Functions
22 General System Security
23 Configuring a chroot jail
24 Advanced Router Options
25 Configuring iptables
26 Using a VPN
Index
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Explanation of ERCB rating scale:
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