You can gauge the depth of coverage of this book by its thickness. Nothing is wasted. Even the inside covers have useful material printed on them: transmission control protocol (TCP) and user datagram protocol (UDP) port numbers inside the front cover, and numerical conversion tables inside the back. Between the covers is an enormous amount of material on TCP/IP networks: 851 pages worth.

The coverage is thoroughly practical. According to the preface, the author’s guiding principal was “Do we need to know this in our day-to-day work?” If not, the material is either omitted, or, if it gives some insight, relegated to a notes section or an appendix. For explanations of how TCP/IP actually operates and its theoretical underpinnings, the Stevens-Comer books are recommended.

Since the author’s concerns are very practical, the choice of operating system is crucial. Linux (the Debian version) and Windows-NT are used throughout, with some mention of Windows 95/98 and Windows 2000. Some material useful with other operating systems can be found on an associated Web site. Almost no mention is made of Novell, or of its protocols, Internetwork packet exchange (IPX) and NetWare core protocol (NCP).

There are five main sections to the book. Part 1 discusses the basic Internet Protocol (IP) system, addresses, masks, routing, and the domain name system. Ethernet in its various forms is used to provide the data link service. Little is said about this service, although the description of the tools used in the book will provide the user with information that can be used to observe how ethernet works.

The well-known tcpdump packet sniffer is used throughout this part as a diagnostic tool. Its options are discussed in some detail, and its use in investigating ailing networks is shown by a number of well thought out examples. The routing part of the IP, and the use of (sub)net masks to direct a packet through the Internet, are described in great detail. Again, the utilities, in this case ping and traceroute, are used to examine the mechanics of routing through a series of nets and subnets. Issues relating to Windows NT and Linux are illustrated by a number of practical examples. The manipulation of routing tables and the placement of gateways are explained. Finally, the use of names rather than numbers to identify hosts is demonstrated, by a discussion of the domain name system (DNS). Three chapters in this part elaborate the use of DNS and its use of various levels for the delegation of routing information.

Part 2 addresses end-user and system applications. The transport layer is managed by two protocols, TCP and UDP, and they are both discussed in this part. There is no real explanation of how these protocols work, or why they were designed as they are, but there is a good exposition of the tools that can be used to observe them. Thus, netstat, ethereal, and ngrep are introduced, and used to peek inside network packets to observe their structure. Email is covered by an examination of simple mail transfer protocol (SMTP), post office protocol (POP3), multi-purpose Internet mail extensions (MIME), Internet message access protocol (IMAP), and a few other systems. The author devotes a chapter to the hypertext transfer protocol (HTTP). The dynamic host configuration protocol (DHCP) is also discussed, along with specific standardized applications such as echo, file transfer protocol (FTP), and daytime.

Part 3 is specific to Microsoft Windows networking. It discusses NetBIOS, WINS, and other related matters to give the reader grounding in how some of the basic functions of Windows can be used to facilitate TCP/IP operations. The logon procedure, browsers, and Windows Explorer are used as examples of how software might be written.

Part 4 is dedicated to connecting a local net to the Internet, and the ensuing implications. Chief among these implications is jeopardized security: if you can see the world, the world can see you. A complete chapter is dedicated to firewalls, while another discusses proxy servers and the scanning of email for viruses and unwanted content. Material explaining connections via dial-up modems using point-to-point (PPP) fill a chapter, and virtual private networking is discussed in another.

A brief epilog and lengthy appendices fill the last pages of the book. The 26 appendices provide specific information on material that is peripheral to the main subject. In some cases, the appendices are thorough documents about specific commands, somewhat like man pages, while in other cases they are tables of numbers.

The author must be taken seriously when he claims that the book deals exclusively with practical matters. You will not find many explanations as to why things work the way they do here. It suffices to know what they can do, and how to make them do it. The book is eminently successful in this goal. It is well written, and quite comprehensive in its coverage of TCP/IP mechanics and applications.