Copyright Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book, and Addison-Wesley was aware of a trademark claim, the designations have been printed with initial capital letters or in all capitals. The author and publisher have taken care in the preparation of this book, but make no expressed or implied warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of the use of the information or programs contained herein. The publisher offers discounts on this book when ordered in quantity for special sales. For more information, please contact: Pearson Education Corporate Sales Division 201W. 103 rd Street Indianapolis, IN 46290 (800) 428-5331
[email protected] Visit AW on the Web: www.awprofessional.com Library of Congress Control Number: 2002106713 Copyright © 2002 by Pearson Education, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form, or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior consent of the publisher. Printed in the United States of America. Published simultaneously in Canada. For information on obtaining permission for use of material from this work, please submit a written request to: Pearson Education, Inc. Rights and Contracts Department 75 Arlington Street, Suite 300 Boston, MA 02116 Fax: (617) 848-7047 Text printed on recycled paper 1 2 3 4 5 6 7 8 9 10—MA—0605040302 First printing, June 2002
Dedication To all those who donated time, money, products, or blood after September 11, 2001. You give hope that humanity's best side may win out over its worst side.
Copyright Preface Many of the designations used by manufacturers sellers to distinguish products are 1970s claimed as 1980s. trademarks. Computer networks have changed our lives. Theyand grew slowly, and mostlytheir unnoticed, in the and In the Where though, those designations in this book,itand was ofWide a trademark claim, the designations 1990s, something appear happened. Perhaps wasAddison-Wesley the availability of theaware World Web (WWW, or Web) and have beenWeb printed with initial capital or innetworks all capitals. graphical browsers, which madeletters computer accessible to Grandma Dorothy and Uncle Stan. Maybe it was that the availability of network connections had reached a critical threshold. Perhaps the quality and quantity of The author and publisher taken care inthreshold. the preparation of this book, make noofexpressed or implied warranty of network-enabled softwarehave passed a critical Possibly it was twobut or all three these things, or something else any kind In and assume responsibility errors or omissions. No liability is assumed for incidental or consequential entirely. any event,no networks becamefor noticeable. Most importantly, the Internet became noticeable. damages in connection with or arising out of the use of the information or programs contained herein. The Internet comprises millions of computers, many of which run servers —software packages designed to listen for The respond publishertooffers discounts on thisfrom bookother whencomputers. ordered inBecause quantitythe for protocols special sales. morethe information, and data transfer requests uponFor which Internet wasplease built contact: were designed to work in a cross-platform manner, both Internet clients and the servers they use run on many different platforms. One of the most popular of these is Linux. Coupled with inexpensive x86 hardware, Linux makes a very Pearson Education Division