TCP/IP Network Administration
`
`Second Edition
`
`Craig Hunt
`
`Cambridge
`
`- Kéiln
`
`- Paris
`
`- Sebastopol
`
`- Tokyo
`
`O’REILLY"
`
`001
`
`US. Patent No. 8,724,622
`
`Apple Inc.
`APLl 1 16
`
`001
`
`Apple Inc.
`APL1116
`U.S. Patent No. 8,724,622
`
`

`

`1".9‘P/ii3 Network Administration, Second Edition
`by Craig I-Iunt
`
`Copyright © 1998, 1992 Craig Hunt. All rights reserved.
`Printed in the United States of America.
`
`Published by O'Reilly & Associates, Inc., 101 Morris Street, Sebastopol, CA 95472.
`
`Edifai'IMike Loukides
`
`Update Editor: Gigi Estabrook
`
`Production Editor: Nicole Gipson Arigo
`
`Printing History:
`
`August 1992:
`
`First Edition.
`
`March 1993:
`
`Minor corrections.
`
`September 1993: Minor corrections.
`
`January 1994:
`
`Minor corrections.
`
`May 1994:
`
`Minor corrections.
`
`_Ianuary 1998:
`
`Second Edition,
`
`Nutshell Handbook and the Nutshell Handbook logo are registered trademarks and The
`javaTM Series is a trademark of O’Reilly & Associates, inc. The association of a crab and the
`topic of TCP/iP is a trademark of O’Reilly & Associates. Inc.
`
`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 O’Reilly &
`Associates, Inc, was aware of a trademark claim, the designations have been printed in caps
`or initial caps.
`
`While every precaution has been taken in the preparation of this book, the publisher assumes
`no responsibility for errors or omissions, or for damages resulting from the use of the
`information contained herein,
`
`This book is printed on acid—free paper with 85% recycled content, 15% post-consumer Waste.
`O’Reilly 8: Associates is committed to using paper with the highest recycled content available
`consistent with high quality,
`
`ISBN: 1—56592—322-7
`
`002
`
`002
`
`

`

`Table of Contents
`
`Preface
`
`I: Overview of TCP/IP
`
`’I‘CP/IP and the Internet
`
`A Data Communications Model
`
`TCP/IP Protocol Architecture
`
`Network Access Layer
`Internet Layer
`
`Transport Layer
`
`'WNH
`
`8
`
`I!
`11
`
`17
`
`ApplicationL21yer21
`
`2: Delz'vem'ng the Data
`
`Addressing, Routing, and Multiplexing
`The IP Address
`
`Subnets
`
`Internet Routing Architecture
`
`The Routing Table
`
`Address Resolution
`Protocols, Ports, and Sockets
`
`003
`
`23
`
`23
`25
`
`31
`
`34
`
`36
`
`39
`42
`
`U
`
`003
`
`

`

`of
`Table of Contents
`
`Network Services
`
`Names and Addresses
`The Host Tabie
`
`48
`
`. 49
`
`.. 50
`
`Domain NameService
`
`. 52
`
`60
`
`.. 71
`
`. 73
`
`. 76
`.. 78
`
`80
`
`.. 81
`
`.83
`.91
`
`..94
`
`.97
`.100
`
`..102
`
`. 104
`
`105
`
`105
`
`106
`
`112
`
`. 118
`
`121
`
`123
`
`t 123
`
`. I37
`I40
`
`.. I53
`162
`
`I64
`
`.164
`
`165
`
`..167
`
`.173
`
`Configuration Servers
`Bootstrap Protocol
`
`File and Print Servers
`
`Getting Started
`
`Connected and Non—Connected Networks
`
`..
`
`Basic Information
`
`Planning Routing
`
`Planning Naming Service.
`
`Informing the Users
`
`Summary
`
`Basic Configuration
`
`Kernel Configuration
`
`Linux Kernel Configuration
`
`The BSD Kernel Configuration File
`The Internet Daemon
`
`Configuring the Interface
`
`The ifeonfig Command
`'l'CP/iP Over a Serial Line
`
`Installing SLIP
`
`Configuring Routing
`
`Common Routing Configurations
`
`The Minimal Routing Table
`
`Building a Static Routing Table
`
`Interior Routing Protocols
`
`004
`
`004
`
`

`

`
`Table of (f‘rmrenfs__________
`
`Exterior Routing Protocols
`
`Gateway Routing Daemon
`
`vii
`
`.. 184
`
`187
`
`I89
`Configuringgated
`.. 200
`
`Configuring DNSName Service
`BIND: UNIX Name Service
`
`Configuring the Resolver
`
`Configuring named
`
`Using nslookup
`
`..
`
`Configuring Network Servers
`
`The Network File System
`Line Printer Daemon
`
`202
`
`.. 202
`
`205
`208
`
`.. 22!
`
`225
`
`226
`
`.. 226
`
`240
`
`245
`
`Network InformationService
`
`A BOOTP Sewer
`
`Managing Distributed Sewers
`
`I 0:
`
`sendmaz‘l
`
`.. 250
`
`258
`
`263
`.. 266
`
`269
`
`.. 271
`
`sendmail’sFunction
`
`.t 272
`
`Running sendinail as aDaemon
`273
`sentlrnail Aliases
`.. 274
`
`The senclmailcf File
`
`sendmail Configuration
`
`Rewriting the Mail Address
`
`Modifying a sendinaiicf File
`
`Testing sendmailcf
`
`I]:
`
`Troubleshooting TCP/IP
`
`Approaching a Problem
`
`Diagnostic Tools. .
`
`Testing Basic Connectivity
`
`Troubleshooting Network Access
`
`Checking Routing
`
`Checking Name Service
`
`276
`
`283
`295
`
`304
`
`308
`
`t. 318
`
`319
`
`320
`
`.. 322
`
`324
`
`328
`
`t. 335
`
`341
`
`005
`
`005
`
`

`

`
`
` m'it' Tobie of Contents
`
`Analyzing Protocol Problems ...................................................................... .. 349
`Protocol Case Study ..................................................................................... i. 352
`Simple Network Management Protocol
`...................................................... .. 356
`Summary ....................................................................................................... .. 36]
`
`12: Network Security .................................................................................. .. 3 62
`
`Security Planning .......................................................................................... .. 363
`User Authentication ...................................................................................... .. 368
`Application Security ..................................................................................... ‘. 384
`Security Monitoring ...................................................................................... .. 385
`Access Control .............................................................................................. .. 393
`Encryption .................................................................................................... .. 396
`Firewalls ........................................................................................................ .. 398
`Words to the Wise ........................................................................................ .. 403
`Summaiy ...................................................................................................... .. 404
`
`13: Internet Information Resources ..................................................... .. 405
`
`The World Wide Web ................................................................................... .. 405
`Anonymous FTP ........................................................................................... .. 408
`
`............................................................................. .. 413
`Finding Files .................
`Retrieving RFCs
`............................................................................................ .. 4J7
`
`Mailing Lists .................................................................................................. .. 420
`The White Pages .......................................................................................... .. 423
`Summary ....................................................................................................... ., 428
`
`A: PPP Tools ................................................................................................. .. 429
`
`B: A gated Reference ................................................................................. .. 449
`
`C: A named Reference .............................................................................. .. 497
`
`D: A dbcpd Reference ................................................................................ .. 519
`
`E: A sendmm'l Reference ......................................................................... .. 532
`
`F: Selected TCP/IP Headers .................................................................... .. 583
`
`Index .................................................................................................................. .. 589
`
`006
`
`006
`
`

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