Linux, Unix, /etc

Danger Will Robinson! You are now entering a condescending Unix user zone!

Review of Linux Network Administrators Guide

What This Book Means To Me

The Linux Network Administrator's Guide (hereinafter known as "NAG") was the first Linux book I bought. Up until them, I'd avoided buying any book that was Linux-specific — not that in that year of 1995 there was much to choose from. First off, I used Linux because it's Unix, and free Unix. That's free as in beer, by the way: I didn't work out the Free Software thing until I was well into using Linux. Because I was focused on Unix, I tended to rely on classic Unix books rather than Linux-specific texts: notably, The Unix Programming Environment (this, as you're all now doubtless sick of hearing, was "The Book That Made Me Want To Use Unix" (TM)). And then, a *book* seemed somehow not to fit in with the whole "hack it youself" Linux mentality; I enjoyed that hacking, all that grepping around in the HOWTOs, all that swearing and pounding the keyboard... well, I suppose I *must* have enjoyed it, or I wouldn't have done it...

This is probably a less personal review than some others in this series, in the sense that I never found NAG that useful; by the time the more promising 2nd edition came out at last, in June of this year, I already knew this stuff, mostly learned the hard way. However, unless stated explicitly otherwise, I am of course speaking of this second edition in what follows.

Outline of the Book

The book is 24 chapters straight-through; but it seems to me that, like Gaul, the whole thing falls into three parts. In the first, the basics of TCP/IP networking are dealt with, taking us from an introduction to the protocols through to configuring networking hardware and getting the network acutally up and running. In the second, we turn to basic low-level features of our working network. In the third, we consider network services, what the network actually exists to do from day to day. I like this structure, though I suppose it's an obvious one. We follow a path from a newbie install through to a working network providing services. Because of the length of the book, I haven't done a blow-by-blow account of each chapter. Instead, here's the TOC, split up as I think it should be, and with remarks on points that particularly held my notice.

Part I

I won't cover the chapters in this first part in any detail. They form an adequete, detailed introduction to the subject.

1 Introduction to Networking

2 Issues of TCP/IP networking

3 Configuring the Networking Hardware

4 Configuring the Serial Hardware

5 Configuring TCP/IP Networking

6 Name Service and Resolver Configuration

Covers the new config file format introduced with BIND 8.

7 Serial Line IP

8 The Point-to-Point Protocol

I got an ISDN line this year, so speaking for myself would have appreciated some coverage of ipppd here. Using ISDN under Linux is a somewhat neglected area so far as documentation goes, and this book is unfortunately no exception: the index doesn't even mention the topic. Running Linux has a good section, and it's a shame not to see NAG building on that.

Part II

Now that we can ping other machines locally or across the Net, our job is far from over.

9 TCP/IP Firewall

One of the more irritating aspects of Linux development in recent years has been the changes to the packet-filtering in the kernel. First we had ipfwadm, then ipchains, and then, just when we were getting used to that, it was announced that 2.4 would have yet a third packet-filtering interface, called netfilter. The last, defintive version? God only knows. Let's hope so. Whatever about that, NAG does a good job of covering all three. A good introduction to firewalls, too, though of course it can't hope to cover all or even most of what you need to know if you're in the business of building firewalls. But it will get you up and running with the Linux tools you'll need for such building.

10 IP Accounting

11 IP Masquerade and Network Address Translation

12 Important Network Features

Runs briefly through inetd, tcpd, /etc/services, /etc/rpc, the r commands, and the configuration of ssh (client & server). tcpd, otherwise known as TCP Wrappers, deserves fuller coverage, and should have got a chapter to itself: it is certainly of less specialist interest than "IPX and the NCP Filesystem", which does.

Part III

With a secured networked in place, the time has come, if we are providing anything more than straight-through access to the Net, to offer our users some local services.

13 The Network Information System

14 The Network File System

15 IPX and the NCP Filesystem

16 Managing Taylor UUCP

17 Electronic Mail

This is a good introduction to the subject, but the section on configuring elm is superfluous; short though it is, it's a waste of space in a book that needs every inch.

18 Sendmail

This is good. Personally I prefer the treatement in TCP/IP Network Administration, but doubtless either will do.

19 Getting Exim Up and Running

If I'd had the time, I would have installed Exim from scratch , and see just how much this chapter helped me — but I hadn't, so I didn't. Oh well.

20 Netnews

Well, I'll admit I'm prejudiced, but to me five chapters totalling 58 pages is too much to devote to Usenet. The service just isn't that important today. If I may repeat myself, it would have been to turn over at least some of this space to covering TCP Wrappers in fuller detail.

21 C News

22 NNTP and the NNTPD Daemon

23 Internet News

24 Newsreader Configuration

Appendices

A Example Network

B Useful Cable Configurations

C Copyright Information

D SAGE

Why This Book Is Important

1st & 2nd editions compared

The 1st ed of this book was somewhat of a disappointment. It did cover some areas well, but left out a lot, for example, no sendmail; and, for the size of the book, far too much about Usenet, a relatively unimportant topic for most Linux users. The 2nd edition shows just how much a book can be improved by being *published* rather than written and released on the web. O'Reilly clearly have a lot to do with making the 2nd edition so much better than the first. This is not to gainsay Terry Dawson's contribution. That name will be well-known to any readers of Linux HOWTOs, and I think he's done a great job in expanding and improving on the original.

Compared with Hunt

Earlier in this series, and before "NAG II" was available, I reviewed TCP/IP Network Administration by Craig Hunt, another O'Reilly offering. Hunt assumes a lot; NAG goes through everything step by step. NAG is great on actually getting TCP/IP up and running on your machine — perhaps this is overkill when today's distributions do so much for you, but it is nice to have nevertheless. The first eight chapters of NAG, pp.1-124, are all about this. Hunt, on the other hand, has a tendency to say, or rather imply, RTFM! Hunt is easier to read straight through. NAG is more a work of reference. When something goes wrong, read the appropriate section, but I'd defy anyone to read it straight through. This is a fault, but not a big one.

NAG is very up-to-date: BIND 8, nsswitch.conf, all three varieties of Linux firewall admin., for example. Hunt, dating from 1996 for the second edition, is already sadly out-of-date in these areas.

Think of this book as all the various HOWTOs concerned with Network consolidated, enhanced, and printed. That's a big bundle.

In conclusion, the 2nd edition of Linux Network Administrator's Guide is indeed so much improved on the first edition that it now makes a well-nigh indispensable companion to Hunt. In fact, the relationship is now reversed; if there is *one* must-get book, it's now NAG rather than Hunt. But I still recommend both.

How To Get This Book

Title: Linux Network Administrators Guide
Author: Olaf Kirch (1st ed.); Terry Dawson (2nd ed.)
Publisher: O'Reilly
ISBN: 1565924002
Price: $34.95
Pages: 474
Date: January 1995 (1st ed.); June 2000 (2nd ed.)

O'Reilly tell us that "The online version of this book, which at time of printing contains exactly the same text as the O'Reilly printed version, is available under the GNU FDL... The book is available online at http://www.linuxdoc.org/LDP/nag/nag.html ..."

Check my Amazon marketplace — I might have a copy of this book for sale.

Paul Dunne 2000

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