Pro Apache

903 Pages·2004·6.55 MB·English

by  Wainwright

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Pro Apache,
Third Edition
PETER WAINWRIGHT
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Pro Apache, Third Edition
Copyright ©2004 by Peter Wainwright
All rights reserved. No part of this work may be reproduced or transmitted in any form or by
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ISBN (pbk): 1-59059-300-6
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Technical Reviewer and Contributing Author: Bradley Bartram
Editorial Board: Dan Appleman, Craig Berry, Gary Cornell, Tony Davis, Steven Rycroft,
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Contents at a Glance
About the Author...............................................................................................xix
About the Technical Reviewer and Contributing Author.................xxi
Chapter 1 Apache and the Internet.......................................................1
Chapter 2 Getting Started with Apache............................................37
Chapter 3 Building Apache the Way You Want It........................101
Chapter 4 Configuring Apache the Way You Want It..................155
Chapter 5 Deciding What the Client Needs...................................231
Chapter 6 Delivering Dynamic Content............................................307
Chapter 7 Hosting More Than One Web Site...................................405
Chapter 8 Improving Apache’s Performance...................................457
Chapter 9 Monitoring Apache................................................................539
Chapter 10 Securing Apache....................................................................597
Chapter 11 Improving Web Server Security.....................................673
Chapter 12 Extending Apache..................................................................727
Index......................................................................................................................843
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Contents
About the Author...............................................................................................xix
About the Technical Reviewer and Contributing Author.................xxi
Chapter 1 Apache and the Internet..............................................1
Apache: The Anatomy of a Web Server.........................................................1
The Apache Source .............................................................................................1
The Apache License............................................................................................1
Support for Apache.............................................................................................2
How Apache Works..............................................................................................3
The Hypertext Transfer Protocol..................................................................7
HTTP Requests and Responses..........................................................................7
HTTP Headers...................................................................................................12
Networking and TCP/IP......................................................................................13
Definitions.........................................................................................................13
Packets and Encapsulation...............................................................................14
ACKs, NAKs, and Other Messages....................................................................15
The TCP/IP Network Model.............................................................................16
Non-IP Protocols...............................................................................................19
IP Addresses and Network Classes...................................................................19
Special IP Addresses..........................................................................................20
Netmasks and Routing......................................................................................21
Web Services: Well-Known Ports......................................................................23
Internet Daemon: The Networking Super Server...........................................24
The Future: IPv6................................................................................................25
Networking Tools...............................................................................................26
Server Hardware...................................................................................................29
Supported Platforms.........................................................................................29
Basic Server Requirements...............................................................................30
Memory..............................................................................................................31
Network Interface..............................................................................................32
Internet Connection.........................................................................................32
Hard Disk and Controller.................................................................................33
Operating System Checklist.............................................................................33
Redundancy and Backup..................................................................................34
Specific Hardware Solutions............................................................................35
Get Someone Else to Do It.............................................................................36
Summary....................................................................................................................36
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Contents
Chapter 2 Getting Started with Apache.................................37
Installing Apache..............................................................................................38
Getting Apache..................................................................................................38
Installing Apache from Binary Distribution....................................................39
Installing Apache from Source.........................................................................41
Installing Apache from Prebuilt Packages.......................................................41
Installing Apache by Hand...............................................................................45
Upgrading Apache.............................................................................................47
Other Issues.......................................................................................................49
Basic Configuration..........................................................................................50
Decisions............................................................................................................50
Introducing the Master Configuration File.....................................................55
Other Basic Configuration Directives..............................................................56
Starting, Stopping, and Restarting the Server.................................57
Starting Apache on Unix...................................................................................58
Starting Apache on Windows...........................................................................59
Invocation Options...........................................................................................60
Restarting the Server.........................................................................................73
Stopping the Server...........................................................................................75
Starting the Server Automatically....................................................................76
Testing the Server............................................................................................81
Testing with a Browser......................................................................................82
Testing from the Command Line or a Terminal Program..............................82
Testing the Server Configuration Without Starting It.....................................85
Getting the Server Status from the Command Line.......................................86
Using Graphical Configuration Tools.......................................................86
Comanche..........................................................................................................87
TkApache...........................................................................................................91
LinuxConf..........................................................................................................91
Webmin..............................................................................................................91
ApacheConf.......................................................................................................97
Other Configuration Tools................................................................................99
Summary..................................................................................................................100
Chapter 3 Building Apache the Way You Want It...........101
Why Build Apache Yourself?.........................................................................101
Verifying the Apache Source Archive.............................................................103
Building Apache from Source......................................................................105
Configuring and Building Apache.................................................................106
Determining Which Modules to Include.......................................................111
Building Apache As a Dynamic Server..........................................................116
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Contents
Changing the Module Order (Apache 1.3)....................................................118
Checking the Generated Configuration........................................................120
Building Apache from Source As an RPM (Apache 2)..................................122
Advanced Configuration.................................................................................124
Configuring Apache’s Layout..........................................................................124
Choosing a Layout Scheme............................................................................124
Choosing a Multiprocessing Module (Apache 2)..........................................132
Rules (Apache 1.3)...........................................................................................135
Building Apache with suExec support...........................................................137
Configuring Apache’s Supporting Files and Scripts.....................................139
Configuring Apache 2 for Cross-Platform Builds.........................................140
Configuring Apache for Production or Debug Builds..................................142
Configuring Apache for Binary Distribution.................................................143
Configuring Apache’s Library and Include Paths..........................................143
Configuring the Build Environment.........................................................144
Building Modules with configure and apxs..........................................146
Adding Third-Party Modules with configure................................................146
Building Modules with apxs...........................................................................148
Installing Modules with apxs..........................................................................150
Generating Module Templates with apxs......................................................151
Overriding apxs Defaults and Using apxs in makefiles................................152
Summary..................................................................................................................153
Chapter 4 Configuring Apache the Way You Want It...155
Where Apache Looks for Its Configuration..........................................155
Configuration File Syntax...............................................................................156
Configuration for Virtual Hosts......................................................................156
Including Multiple Configuration Files.........................................................157
Per-Directory Configuration..........................................................................159
Conditional Configuration.............................................................................160
How Apache Structures Its Configuration............................................163
Apache’s Container Directives........................................................................164
Directive Types and Locations.......................................................................168
Where Directives Can Go................................................................................171
Container Scope and Nesting.........................................................................172
How Apache Combines Containers and Their Contents.............................174
Legality of Directives in Containers...............................................................175
Options and Overrides....................................................................................176
Enabling and Disabling Features with Options............................................176
Overriding Directives with Per-Directory Configuration.............................179
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Contents
Restricting Access with allow and deny..............................................182
Controlling Access by Name...........................................................................183
Controlling Access by IP Address...................................................................184
Controlling Subnet Access by Network and Netmask..................................185
Controlling Access by HTTP Header.............................................................186
Combining Host-Based Access with User Authentication...........................187
Overriding Host-Based Access.......................................................................188
Directory Listings..........................................................................................188
Enabling and Disabling Directory Indices....................................................189
How mod_autoindex Generates the HTML Page.........................................190
Controlling Which Files Are Seen with IndexIgnore.....................................196
Controlling the Sort Order..............................................................................197
Assigning Icons................................................................................................199
Assigning Descriptions...................................................................................202
Apache’s Environment......................................................................................203
Setting, Unsetting, and Passing Variables from the Shell.............................204
Setting Variables Conditionally......................................................................205
Special Browser Variables...............................................................................207
Detecting Robots with BrowserMatch...........................................................209
Passing Variables to CGI.................................................................................209
Conditional Access Control............................................................................210
Caveats with SetEnvIf vs. SetEnv....................................................................210
Setting Variables with mod_rewrite...............................................................211
Controlling Request and Response Headers..........................................211
Setting Custom Response Headers................................................................213
Setting Custom Request Headers...................................................................215
Inserting Dynamic Values into Headers........................................................216
Setting Custom Headers Conditionally.........................................................217
Retrieving Response Headers from Metadata Files......................................217
Setting Expiry Times.......................................................................................219
Sending Content As-Is....................................................................................222
Controlling the Server Identification Header.................................223
Sending a Content Digest.............................................................................224
Handling the Neighbors.................................................................................225
Controlling Robots with robots.txt................................................................226
Controlling Robots in HTML..........................................................................227
Controlling Robots with Access Control........................................................227
Attracting Robots.............................................................................................228
Making Sure Robots Index the Right Information........................................228
Known Robots, Bad Robots, and Further Reading.......................................229
Summary..................................................................................................................229
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Contents
Chapter 5 Deciding What the Client Needs........................231
Content Handling and Negotiation...........................................................231
File Types.........................................................................................................232
File Encoding...................................................................................................236
File Languages.................................................................................................243
File Character Sets...........................................................................................245
Handling URLs with Extra Path Information................................................247
Content Negotiation.......................................................................................248
Content Negotiation with MultiViews...........................................................250
File Permutations and Valid URLs with MultiViews.....................................256
Magic MIME Types..........................................................................................260
Error and Response Handling......................................................................264
How Apache Handles Errors...........................................................................265
Error and Response Codes.............................................................................265
The ErrorDocument Directive.......................................................................266
Limitations of ErrorDocument......................................................................270
Aliases and Redirection...............................................................................271
Aliases and Script Aliases................................................................................271
Redirections.....................................................................................................273
Rewriting URLs with mod_rewrite.................................................................277
Server-Side Image Maps.................................................................................300
Matching Misspelled URLS............................................................................305
Summary..................................................................................................................306
Chapter 6 Delivering Dynamic Content..................................307
Server-Side Includes......................................................................................308
Enabling SSI.....................................................................................................309
Format of SSI Commands...............................................................................311
The SSI Command Set....................................................................................312
SSI Variables.....................................................................................................312
Passing Trailing Path Information to SSIs
(and Other Dynamic Documents).................................................................315
Setting the Date and Error Format.................................................................316
Templating with SSIs.......................................................................................317
Caching Server-Parsed Documents...............................................................319
Identifying Server-Parsed Documents by Execute Permission...................320
CGI: The Common Gateway Interface.........................................................321
CGI and the Environment..............................................................................321
Configuring Apache to Recognize CGI Scripts.............................................323
Setting Up a CGI Directory with ExecCGI: A Simple Way............................327
Triggering CGI Scripts on Events...................................................................330
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Contents
ISINDEX-Style CGI Scripts and Command Line Arguments................332
Writing and Debugging CGI Scripts.........................................................333
A Minimal CGI Script......................................................................................333
Interactive Scripts: A Simple Form................................................................337
Adding Headers...............................................................................................338
Debugging CGI Scripts....................................................................................339
Setting the CGI Daemon Socket.....................................................................345
Limiting CGI Resource Usage.........................................................................346
Actions, Handlers, and Filters................................................................347
Handlers...........................................................................................................348
Filters................................................................................................................354
Dynamic Content and Security....................................................................363
CGI Security Issues..........................................................................................363
Security Advice on the Web............................................................................364
Security Issues with Apache CGI Configuration...........................................364
An Example of an Insecure CGI Script..........................................................365
Known Insecure CGI Scripts...........................................................................370
CGI Wrappers...................................................................................................370
Security Checklist............................................................................................380
Inventing a Better CGI Script with FastCGI......................................381
Summary..................................................................................................................403
Chapter 7 Hosting More Than One Web Site........................405
Implementing User Directories with UserDir......................................406
Enabling and Disabling Specific Users..........................................................407
Redirecting Users to Other Servers................................................................408
Alternative Ways to Implement User Directories.........................................409
Separate Servers..............................................................................................410
Restricting Apache’s Field of View..................................................................411
Specifying Different Configurations and Server Roots................................412
Starting Separate Servers from the Same Configuration.............................412
Sharing External Configuration Files.............................................................413
IP-Based Virtual Hosting.............................................................................414
Multiple IPs, Separate Networks, and Virtual Interfaces..............................415
Configuring What Apache Listens To.............................................................416
Defining IP-Based Virtual Hosts.....................................................................418
Virtual Hosts and the Server-Level Configuration........................................421
Specifying Virtual Host User Privileges..........................................................422
Excluded Directives.........................................................................................426
Default Virtual Hosts....................................................................................427
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