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Books: A User's Report

Elizabeth Zinkann

During this month, there were more books released than I have space to review. Included in this column are the new Zen and the Art of the Internet: A Beginner's Guide by Brendan P. Kehoe (Prentice Hall), The Online User's Encyclopedia: Bulletin Boards and Beyond by Bernard Aboba (Addison-Wesley), UNIX Networks: An Overview for System Administrators by Bruce H. Hunter and Karen Bradford Hunter (Prentice Hall), The Internet Complete Reference by Harley Hahn and Rick Stout (Osborne McGraw-Hill), The Internet Yellow Pages also by Harley Hahn and Rick Stout (Osborne McGraw-Hill), Firewalls and Internet Security: Repelling the Wily Hacker by William R. Cheswick and Steven M. Bellovin (Addison-Wesley Professional Computing Series), and The Internet Navigator by Paul Gilster, Foreword by Vinton G. Cerf (John Wiley and Sons, Inc.). I hope you enjoy them as much as I did!

Zen and the Art of the Internet
A Beginner's Guide

Third Edition by Brendan P. Kehoe
Prentice Hall
ISBN 0-13-121492-6

In this "New & Improved" edition, Kehoe has added several new developments to his introduction to the Internet. He looks at the problems that chain letters can cause, showing why they should not be sent; explores the bulletin-board systems (BBS's) on the Internet and describes several of them; and presents several tools that can search the Internet, including the Wide Area Information Server (WAIS), Veronica, and Netfind. This edition contains information on communicating with the White House, MTV, the Online Book Initiative, Internet Talk Radio, and the Online Career Center, as well as a chapter on finding further information about the Internet. An appendix covers current country codes, including the Russian Federation and the new countries that were part of the former Soviet Union.

I reviewed the first edition of Kehoe's book. Since then, it has almost doubled in size and is much easier to read due to format and typesetting changes. The quality of the book remains excellent and the author furnishes complete addresses of products that he mentions. This book provides a worthwhile resource and guide to the Internet.

The Online User's Encyclopedia: Bulletin Boards and Beyond
by Bernard Aboba
ISBN 0-201-62214-9

Aboba has produced a treasure trove of information about telecommunications and computer networks. The guide begins with Quickstart, which was designed to provide the beginner with basic information about communications and online activities. It presents sections on hardware, software, communications settings, bulletin boards, networks, and global networks. The Quickstart section also discusses what users of different machines -- Macintosh, DOS PC, or UNIX workstation -- can accomplish online.

The second section is devoted to the Internet. It provides a basic explanation of the Internet, describes Internet service providers, and considers privacy and security issues. Aboba discusses electronic mail, different file transfers, online libraries, and Usenet. He also details real-time conversations, such as Internet Talk Radio; information servers, including WAIS, Gopher, Veronica, and the World Wide Web (W3), plus TCP/IP.

The "Store and Forward Network Guide" focuses on UUCP, BITNET, FidoNet, EchoMac, RIME, and ILink, describing the network, outlining their benefits, and telling you how to join them. The Tutorial discusses such topics as "How To Save Money On Your Phone Bill," "File Transfers Between Macs, PCs, and UNIX," file conversion, compression, and home control, and includes a diverting chapter on "Emoticons and Other Jargon". The final section, "Memories and Visions," presents several histories of different networks as well as what the future may bring.

The appendices include a bibliography, a review of selected products, a directory of online resources, information on cables, UNIX information, conference listings for different networks, and a glossary of terms. This book provides a wealth of information for any user, regardless of his/her platform or level of experience. It is easy to spend hours perusing this extremely worthwhile guide.

UNIX Networks
An Overview for System Administrators

by Bruce H. Hunter and Karen Bradford Hunter
Prentice Hall
ISBN 0-13-089087-1

Due to technological advances in both hardware and software and to the current popularity of online communications, the UNIX system administrator must also be a UNIX network administrator. Bruce and Karen Hunter have divided this book into three sections: basic knowledge, intermediate topics, and advanced topics. The introductory chapter addresses networking models and protocol suites, including the International Standards Organization Open Systems Interconnection (ISO/OSI) model, the TCP/IP-Ethernet protocols, and the IEEE 802.3 protocols. The TCP/IP-Ethernet protocol presented is a shorter UNIX model that includes the IEEE 802.3 protocols. The Hunters tackle the difficult subject of data encapsulation by comparing it to a postal service with three agencies. The example discusses the concepts of packets, datagrams, and frames clearly and sensibly. A technical approach to data encapsulation follows the metaphorical one.

The section on basic knowledge continues with chapters on network topology and the network media used, i.e., thicknet, thinnet, twisted-wire pair, or fiber optic cable; active devices, including transceivers, repeaters, bridges, routers, gateways, and other specialized devices, and also including a discussion of which device is more appropriate for different uses; and network design, creation, and implementation. The network design chapter lists factors to consider when designing a network and prior to purchasing any components, then presents some example networks and describes how they were designed. Other topics addressed in the basics section include addressing, Ethernet-TCP/IP Protocols, routers, file servers, YP servers, print servers, clients, and setting up workstations.

The intermediate section features "Security and Access Control," plus "Monitoring and Diagnostics." Different systems use different ways of providing security. Some use Kerberos, from MIT's Project Athena, and some use secure NFS. System V Release 4 and AIX both use a shadow file to shield the password encryption in the passwd file from the users. Which diagnostics or monitoring tools you use may depend on the size of your network. If commercial products aren't in your budget, you'll want to use some of the tools already on your system, such as ping, spray, vmstat, pstat, netstat, etherfind, and rpcinfo. Bruce and Karen Hunter describe these tools and tell you how to use them. They also explain the terms protocol analyzer, network analyzer, network monitor, and network manager, as well as discussing some specific products, including SunNet Manager, SynOptic's Network Manager, and Concord's Trakker Network Monitoring System.

The advanced section addresses "Mail and Sendmail Administration," "DNS and BIND," "Administering the X Window System," and "Network Scenarios." The X Window System is treated from the administrator's perspective rather than from the user's viewpoint. On the theory that it's easier for an administrator to cope with problems if he/she knows something about the system, the Hunters provide a basic introduction to the X Window System, including a glossary of terms and an explanation of the X client/server relationship. They present an installation summary and installation considerations, such as what the user might want and how to accomplish the task, as well as some answers to problems that might arise during installation.

A particular useful chapter is "Network Scenarios," which presents several networking problems and solutions. The authors don't just give the solution to the problem, however; they present guidelines for handling future problems:

Once you solve a problem, take the time to find out what happened. Then, when the same problem comes up, you know exactly what to do [page 357].

UNIX Networks is an excellent resource for installing and administer UNIX networks. It is both a practical guide to UNIX networks and an in-depth look at many topics not usually examined in administration books. In addition to code examples and screen outputs, the authors have included diagrams and figures that help clarify concepts. The writing style is comfortable, and the authors give the reader a history of different ideas, as well as a glimpse of what the future may hold. The present is described in detail.

Bruce H. and Karen Bradford Hunter previously published root magazine (a forerunner to Sys Admin), and UNIX Networks displays a small box featuring the root dragon on the cover. The authors have produced an excellent addition to the UNIX library. I highly recommend it for system administrators, network administrators, and UNIX users in general.

The Internet Complete Reference
by Harley Hahn and Rick Stout
Osborne McGraw-Hill
ISBN 0-07-881980-6

Hahn and Stout have produced a user-friendly guide to the Internet. They begin with an introduction to the Internet, then explains how to use this book and considers whether or not the reader needs to know UNIX. The next chapter explains how the Internet works, then covers hosts and terminals and client/server systems, including the X Window System. The authors then present a quick and often entertaining tour of Internet resources, including electronic mail, Usenet, Anonymous FTP, Archie, Gopher, WAIS servers, and the World-Wide Web. At this point, they display a roadmap which contains the Internet resources, a brief description of each resource, and the respective chapters that discuss it.

Hahn and Stout recommend that users begin by reading the first four chapters, which feature sections on networks, TCP/IP, types of Internet connections, and Internet addressing. Once done with the introductory material, the reader may choose which sections of the book to examine next. Possible choices include excellent explanations of the Internet mail system, Telnet, Usenet, the rn, trn, nn, and tin newsreaders, Anonymous FTP, Archie, Gopher, Veronica, Jughead, WAIS, the World-Wide Web, and Mailing Lists. The authors also include a catalog of Internet Resources, public access to the Internet, and a list of Usenet discussion groups. In addition, Hahn and Stout explain how to discover public information about an individual using the Finger service, how to participate in discussions using Internet Relay Chat or Talk, and what file formats are commonly used on the Internet.

This book presents a great deal of useful information pertaining to the Internet. The authors explore each topic thoroughly and discuss the different services in detail, providing examples, a summary of different ways to utilize the service, and messages the user may receive and what they mean. The chapters are divided into small segments, which enables the busy reader to digest small portions without disrupting the book's continuity. I recommend this book for anyone interested in the Internet, whether advanced or would-be traveler.

The Internet Yellow Pages
by Harley Hahn and Rick Stout
Osborne McGraw-Hill
ISBN 0-07-882023-5

This book provides the Internet user with a directory of Internet resources and Usenet newsgroups and includes both descriptions of the resources and instruction on how to connect to them. It can also become a way to spend hours on the Internet without logging on to a computer. The illustrations and the accompanying texts can sidetrack the reader very easily -- from agriculture and art to four sections on government to health and medicine, it doesn't take much effort to lose track of time. Other subjects include literature, music, jokes, jobs, cartoons, youth, quotations, pets, and travel, as well as, of course, computers, software, and operating systems.

The list goes on, with games, trivia, and the Swedish Chef. The Internet Yellow Pages identifies over 2400 different Internet resources in addition to the Usenet newsgroups, in alphabetical order. This is the logical way to approach the Internet. This book won't stay on any bookshelf long. It will be used too often.

Firewalls and Internet Security
Repelling the Wily Hacker

by William R. Cheswick and Steven M. Bellovin
Addison-Wesley Professional Computing Series
ISBN 0-201-63357-4

Cheswick and Bellovin address the problems of security facing today's system administrator. They begin by asking what we are trying to protect and from whom we are shielding the system's resources. The answers to these questions, along with budget considerations, will determine an organization's security policy. The authors advocate the use of firewalls and define them by the properties that a firewall should possess.

This book uses a bomb icon to indicate serious security risks. The first such symbol appears by the protecting passwords section. As most system administrators know, most users do not select truly secure passwords; consequently, user accounts are often easy prey for an attacker. Cheswick and Bellovin offer suggestions for defending the password file against such attacks. This section also presents an overview of the TCP/IP protocol suite. The authors explore the different layers, and produce a diagram of a sample TCP session between client and server. As they look at routers, DNS, standard services, RPC-based and file transfer protocols, information services, and the X11 System, the areas of serious risk seem to proliferate. The authors make very clear just how easy it is to infiltrate an unprotected system.

The second section, entitled "Building Your Own Firewall," examines firewall gateways, creating an application gateway, authentication, gateway tools, and the hacker's tools. Cheswick and Bellovin begin by properly defining gateways, firewalls, and the firewall philosophy. They discuss what a firewall may cost and where firewalls should be positioned within a system, then go on to describe the limitations of a firewall. Some of the tools featured here are proxylib, proxy, socks (no relation to Chelsea's cat), syslog, tcpdump, ping, traceroute, and dig.

"A Look Back," the third section of the book, details breaking and entering and presents an informative example, entitled "An Evening with Berferd." This chapter recounts the attempts made by a hacker to compromise a system and the steps taken to thwart him. Since no policy was in place to protect the system from this sort of attack, the responses were necessarily ad hoc. The final section of the book, "Odds and Ends," includes "Legal Considerations," "Secure Communications Over Insecure Networks," and "Where Do We Go From Here?" The appendices include "Useful Free Stuff," "TCP and UDP Ports," "Recommendations to Vendors," and a very complete Bibliography.

Cheswick and Bellovin demonstrate how easy it may be for a hacker to invade your system. Fortunately, they provide guidelines that system administrators may follow to protect their systems against intrusions. They also ask questions that focus on how secure your system really is and introduce answers to help you defend that system. Firewalls and Internet Security merits the attention of system administrators everywhere.

The Internet Navigator
by Paul Gilster
Foreword by Vinton G. Cerf
John Wiley and Sons, Inc.
ISBN 0-471-59782-1

Gilster demonstrates how exciting the Internet can be by displaying several places to visit, then continues by defining the Internet and telling how it works. He explains how to obtain an Internet account and how to access it. He provides the UNIX knowledge that you will need to effectively use the Internet.

Subjects discussed include FTP, Telnet, electronic mail, BITNET, and USENET. To help readers learn how to find resources and how to conduct a search, Gilster introduces Gopher, Veronica, Wide Area Information Servers (WAIS), and the World-Wide Web. To further facilitate the Internet experience, he provides an Internet Toolbox, containing Finger, NSLOOKUP, Netfind, WHOIS, the CSO name server, and the Knowbot Information Service. The toolbox also includes BITNET names, Campus Wide Information Systems (CWIS), talk, and Internet Relay Chat (IRC). The last section of the book consists of a directory of Internet Resources, a discussion of the future of the Internet, and an appendix containing dial-up Internet service providers.

The primary strength of The Internet Navigator resides in its diagrams and screen outputs. The author may use two or three different screens to demonstrate how one example progresses. The reader knows what his monitor will reflect at the beginning, middle, and end of a session or activity. Gilster's careful presentation of online services shows readers how to use these services effectively with the Internet. He has produced a clearly written and worthwhile book for the Internet traveler.

About the Author

Elizabeth Zinkann has been involved in the UNIX and C environments for the past 11 years. She is currently a UNIX and C consultant, and one of her specialities is UNIX education. In addition to her computer science background, she also has a degree in English. Elizabeth can be reached via CompuServe at 71603,2201 (Internet format: