System Administrator's Guide - Deployment, Configuration, and Administration of Fedora 16

566 Pages·2011·6.25 MB·English

Fedora 16
System
Administrator's Guide
Deployment, Configuration, and Administration of Fedora 16
Jaromír Hradílek
Douglas Silas
Martin Prpič
Eva Kopalová
Eliška Slobodová
Tomáš Čapek
Petr Kovář
Miroslav Svoboda
System Administrator's Guide
John Ha
David O'Brien
Michael Hideo
Don Domingo
Fedora 16 System Administrator's Guide
Deployment, Configuration, and Administration of Fedora 16
Edition 1
Author Jaromír Hradílek [email protected]
Author Douglas Silas [email protected]
Author Martin Prpič [email protected]
Author Eva Kopalová [email protected]
Author Eliška Slobodová [email protected]
Author Tomáš Čapek [email protected]
Author Petr Kovář [email protected]
Author Miroslav Svoboda [email protected]
Author John Ha
Author David O'Brien
Author Michael Hideo
Author Don Domingo
Copyright © 2011 Red Hat, Inc. and others.
The text of and illustrations in this document are licensed by Red Hat under a Creative Commons
Attribution–Share Alike 3.0 Unported license ("CC-BY-SA"). An explanation of CC-BY-SA is available
at http://creativecommons.org/licenses/by-sa/3.0/. The original authors of this document, and Red Hat,
designate the Fedora Project as the "Attribution Party" for purposes of CC-BY-SA. In accordance with
CC-BY-SA, if you distribute this document or an adaptation of it, you must provide the URL for the
original version.
Red Hat, as the licensor of this document, waives the right to enforce, and agrees not to assert,
Section 4d of CC-BY-SA to the fullest extent permitted by applicable law.
Red Hat, Red Hat Enterprise Linux, the Shadowman logo, JBoss, MetaMatrix, Fedora, the Infinity
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For guidelines on the permitted uses of the Fedora trademarks, refer to https://fedoraproject.org/wiki/
Legal:Trademark_guidelines.
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and/or other countries.
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countries.
All other trademarks are the property of their respective owners.
The System Administrator's Guide documents relevant information regarding the deployment,
configuration, and administration of Fedora 16. It is oriented towards system administrators with a
basic understanding of the system.

Preface xv
1. Target Audience ............................................................................................................ xv
2. How to Read this Book .................................................................................................. xv
3. Document Conventions ................................................................................................ xviii
3.1. Typographic Conventions .................................................................................. xviii
3.2. Pull-quote Conventions ....................................................................................... xix
3.3. Notes and Warnings ........................................................................................... xx
4. Feedback ...................................................................................................................... xx
5. Acknowledgments ......................................................................................................... xxi
I. Basic System Configuration 1
1. Configuring the Language and Keyboard 3
1.1. Changing the Language ....................................................................................... 3
1.2. Changing the Date, Time, and Numeric Format ...................................................... 4
1.3. Changing the Keyboard Layout ............................................................................. 6
1.4. Viewing the Current Configuration ......................................................................... 8
2. Configuring the Date and Time 9
2.1. Using the Date and Time Configuration Tool .......................................................... 9
2.2. Using the Command Line Tools .......................................................................... 10
2.2.1. Changing the Date ................................................................................... 10
2.2.2. Changing the Time .................................................................................. 10
2.2.3. Configuring the Network Time Protocol ..................................................... 10
2.3. Additional Resources .......................................................................................... 12
2.3.1. Installed Documentation ........................................................................... 12
3. Managing Users and Groups 13
3.1. Introduction to Users and Groups ........................................................................ 13
3.1.1. User Private Groups ................................................................................ 13
3.1.2. Shadow Passwords ................................................................................. 13
3.2. Using the User Accounts Tool ............................................................................. 14
3.2.1. Configuring an Account ............................................................................ 15
3.2.2. Adding a New User ................................................................................. 16
3.2.3. Removing a User ..................................................................................... 16
3.3. Using the User Manager Tool ............................................................................. 17
3.3.1. Viewing Users and Groups ....................................................................... 17
3.3.2. Adding a New User ................................................................................. 18
3.3.3. Adding a New Group ............................................................................... 19
3.3.4. Modifying User Properties ........................................................................ 19
3.3.5. Modifying Group Properties ...................................................................... 20
3.4. Using Command Line Tools ................................................................................ 21
3.4.1. Adding a New User ................................................................................. 21
3.4.2. Adding a New Group ............................................................................... 24
3.4.3. Enabling Password Aging ......................................................................... 25
3.4.4. Enabling Automatic Logouts ..................................................................... 26
3.4.5. Creating Group Directories ....................................................................... 27
3.5. Additional Resources .......................................................................................... 28
3.5.1. Installed Documentation ........................................................................... 28
II. Package Management 29
4. Yum 31
4.1. Checking For and Updating Packages ................................................................. 31
4.1.1. Checking For Updates ............................................................................. 31
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4.1.2. Updating Packages .................................................................................. 32
4.1.3. Preserving Configuration File Changes ..................................................... 34
4.2. Packages and Package Groups .......................................................................... 34
4.2.1. Searching Packages ................................................................................ 34
4.2.2. Listing Packages ..................................................................................... 34
4.2.3. Displaying Package Information ................................................................ 37
4.2.4. Installing Packages .................................................................................. 38
4.2.5. Removing Packages ................................................................................ 40
4.2.6. Working with Transaction History .............................................................. 41
4.3. Configuring Yum and Yum Repositories ............................................................... 46
4.3.1. Setting [main] Options .............................................................................. 46
4.3.2. Setting [repository] Options ...................................................................... 49
4.3.3. Using Yum Variables ............................................................................... 50
4.3.4. Viewing the Current Configuration ............................................................. 51
4.3.5. Adding, Enabling, and Disabling a Yum Repository .................................... 52
4.3.6. Creating a Yum Repository ...................................................................... 53
4.4. Yum Plug-ins ..................................................................................................... 54
4.4.1. Enabling, Configuring, and Disabling Yum Plug-ins .................................... 54
4.4.2. Installing Additional Yum Plug-ins ............................................................. 55
4.4.3. Plug-in Descriptions ................................................................................. 55
4.5. Additional Resources .......................................................................................... 59
5. PackageKit 61
5.1. Updating Packages with Software Update ............................................................ 61
5.1.1. Setting the Update-Checking Interval ........................................................ 62
5.1.2. Setting the Software Sources ................................................................... 62
5.2. Using Add/Remove Software .............................................................................. 63
5.2.1. Refreshing Software Sources (Yum Repositories) ...................................... 64
5.2.2. Finding Packages with Filters ................................................................... 64
5.2.3. Installing and Removing Packages (and Dependencies) ............................. 66
5.2.4. Installing and Removing Package Groups ................................................. 68
5.2.5. Viewing the Transaction Log .................................................................... 69
5.3. PackageKit Architecture ...................................................................................... 70
5.4. Additional Resources .......................................................................................... 71
III. Networking 73
6. Network Interfaces 75
6.1. Network Configuration Files ................................................................................ 75
6.2. Interface Configuration Files ................................................................................ 76
6.2.1. Ethernet Interfaces .................................................................................. 76
6.2.2. Channel Bonding Interfaces ..................................................................... 79
6.2.3. Alias and Clone Files ............................................................................... 80
6.2.4. Dialup Interfaces ...................................................................................... 81
6.2.5. Other Interfaces ....................................................................................... 83
6.3. Interface Control Scripts ..................................................................................... 83
6.4. Configuring Static Routes ................................................................................... 85
6.5. Network Function Files ....................................................................................... 87
6.6. Additional Resources .......................................................................................... 87
6.6.1. Installed Documentation ........................................................................... 87
IV. Infrastructure Services 89
7. Services and Daemons 91
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7.1. Configuring Services ........................................................................................... 91
7.1.1. Enabling the Service ................................................................................ 91
7.1.2. Disabling the Service ............................................................................... 92
7.2. Running Services ............................................................................................... 92
7.2.1. Checking the Service Status .................................................................... 92
7.2.2. Running the Service ................................................................................ 94
7.2.3. Stopping the Service ................................................................................ 94
7.2.4. Restarting the Service .............................................................................. 94
7.3. Additional Resources .......................................................................................... 95
7.3.1. Installed Documentation ........................................................................... 95
7.3.2. Related Books ......................................................................................... 95
8. Configuring Authentication 97
8.1. The Authentication Configuration Tool ................................................................. 97
8.1.1. Identity & Authentication ........................................................................... 97
8.1.2. Advanced Options .................................................................................. 101
8.1.3. Command Line Version .......................................................................... 103
8.2. The System Security Services Daemon (SSSD) ................................................. 107
8.2.1. What is SSSD? ..................................................................................... 107
8.2.2. SSSD Features ...................................................................................... 107
8.2.3. Setting Up SSSD ................................................................................... 109
8.2.4. Configuring Services .............................................................................. 116
8.2.5. Configuring Domains .............................................................................. 118
8.2.6. Setting Up Kerberos Authentication ......................................................... 126
8.2.7. Configuring a Proxy Domain ................................................................... 129
8.2.8. Troubleshooting ..................................................................................... 131
8.2.9. SSSD Configuration File Format ............................................................. 135
9. OpenSSH 137
9.1. The SSH Protocol ............................................................................................ 137
9.1.1. Why Use SSH? ..................................................................................... 137
9.1.2. Main Features ....................................................................................... 138
9.1.3. Protocol Versions ................................................................................... 138
9.1.4. Event Sequence of an SSH Connection .................................................. 138
9.2. An OpenSSH Configuration ............................................................................... 140
9.2.1. Configuration Files ................................................................................. 140
9.2.2. Starting an OpenSSH Server .................................................................. 142
9.2.3. Requiring SSH for Remote Connections .................................................. 143
9.2.4. Using a Key-Based Authentication .......................................................... 143
9.3. OpenSSH Clients ............................................................................................. 146
9.3.1. Using the ssh Utility ............................................................................... 147
9.3.2. Using the scp Utility .............................................................................. 148
9.3.3. Using the sftp Utility ............................................................................ 148
9.4. More Than a Secure Shell ................................................................................ 149
9.4.1. X11 Forwarding ..................................................................................... 149
9.4.2. Port Forwarding ..................................................................................... 150
9.5. Additional Resources ........................................................................................ 151
9.5.1. Installed Documentation ......................................................................... 151
9.5.2. Useful Websites ..................................................................................... 151
V. Servers 153
10. DHCP Servers 155
10.1. Why Use DHCP? ............................................................................................ 155
10.2. Configuring a DHCP Server ............................................................................ 155
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10.2.1. Configuration File ................................................................................. 155
10.2.2. Lease Database ................................................................................... 158
10.2.3. Starting and Stopping the Server .......................................................... 159
10.2.4. DHCP Relay Agent .............................................................................. 160
10.3. Configuring a DHCP Client .............................................................................. 160
10.4. Configuring a Multihomed DHCP Server .......................................................... 161
10.4.1. Host Configuration ............................................................................... 162
10.5. DHCP for IPv6 (DHCPv6) ............................................................................... 164
10.6. Additional Resources ...................................................................................... 164
10.6.1. Installed Documentation ....................................................................... 165
11. DNS Servers 167
11.1. Introduction to DNS ........................................................................................ 167
11.1.1. Nameserver Zones ............................................................................... 167
11.1.2. Nameserver Types ............................................................................... 167
11.1.3. BIND as a Nameserver ........................................................................ 168
11.2. BIND .............................................................................................................. 168
11.2.1. Configuring the named Service ............................................................. 168
11.2.2. Editing Zone Files ................................................................................ 176
11.2.3. Using the rndc Utility ............................................................................ 182
11.2.4. Using the dig Utility .............................................................................. 185
11.2.5. Advanced Features of BIND ................................................................. 187
11.2.6. Common Mistakes to Avoid .................................................................. 188
11.2.7. Additional Resources ............................................................................ 189
12. Web Servers 191
12.1. The Apache HTTP Server ............................................................................... 191
12.1.1. New Features ...................................................................................... 191
12.1.2. Notable Changes ................................................................................. 191
12.1.3. Updating the Configuration ................................................................... 191
12.1.4. Running the httpd Service .................................................................... 192
12.1.5. Editing the Configuration Files .............................................................. 193
12.1.6. Working with Modules .......................................................................... 224
12.1.7. Setting Up Virtual Hosts ....................................................................... 225
12.1.8. Setting Up an SSL Server .................................................................... 225
12.1.9. Additional Resources ............................................................................ 232
13. Mail Servers 233
13.1. Email Protocols .............................................................................................. 233
13.1.1. Mail Transport Protocols ....................................................................... 233
13.1.2. Mail Access Protocols .......................................................................... 234
13.2. Email Program Classifications ......................................................................... 236
13.2.1. Mail Transport Agent ............................................................................ 236
13.2.2. Mail Delivery Agent .............................................................................. 237
13.2.3. Mail User Agent ................................................................................... 237
13.3. Mail Transport Agents ..................................................................................... 237
13.3.1. Postfix ................................................................................................. 237
13.3.2. Sendmail ............................................................................................. 239
13.3.3. Fetchmail ............................................................................................. 244
13.3.4. Mail Transport Agent (MTA) Configuration ............................................. 248
13.4. Mail Delivery Agents ....................................................................................... 249
13.4.1. Procmail Configuration ......................................................................... 249
13.4.2. Procmail Recipes ................................................................................. 250
13.5. Mail User Agents ............................................................................................ 255
13.5.1. Securing Communication ...................................................................... 255
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13.6. Additional Resources ...................................................................................... 257
13.6.1. Installed Documentation ....................................................................... 257
13.6.2. Useful Websites ................................................................................... 258
13.6.3. Related Books ..................................................................................... 259
14. Directory Servers 261
14.1. OpenLDAP ..................................................................................................... 261
14.1.1. Introduction to LDAP ............................................................................ 261
14.1.2. Installing the OpenLDAP Suite .............................................................. 263
14.1.3. Configuring an OpenLDAP Server ......................................................... 265
14.1.4. Running an OpenLDAP Server ............................................................. 270
14.1.5. Configuring a System to Authenticate Using OpenLDAP ......................... 271
14.1.6. Additional Resources ............................................................................ 272
15. File and Print Servers 275
15.1. Samba ........................................................................................................... 275
15.1.1. Introduction to Samba .......................................................................... 275
15.1.2. Samba Daemons and Related Services ................................................. 276
15.1.3. Connecting to a Samba Share .............................................................. 277
15.1.4. Configuring a Samba Server ................................................................. 279
15.1.5. Starting and Stopping Samba ............................................................... 280
15.1.6. Samba Server Types and the smb.conf File ........................................ 281
15.1.7. Samba Security Modes ........................................................................ 288
15.1.8. Samba Account Information Databases ................................................. 290
15.1.9. Samba Network Browsing ..................................................................... 291
15.1.10. Samba with CUPS Printing Support ..................................................... 292
15.1.11. Samba Distribution Programs .............................................................. 292
15.1.12. Additional Resources .......................................................................... 297
15.2. FTP ............................................................................................................... 299
15.2.1. The File Transfer Protocol .................................................................... 299
15.2.2. FTP Servers ........................................................................................ 299
15.2.3. Files Installed with vsftpd ................................................................. 300
15.2.4. Starting and Stopping vsftpd ............................................................. 301
15.2.5. vsftpd Configuration Options .............................................................. 302
15.2.6. Additional Resources ............................................................................ 311
15.3. Printer Configuration ....................................................................................... 312
15.3.1. Starting the Printer Configuration Tool ................................................... 312
15.3.2. Starting Printer Setup ........................................................................... 312
15.3.3. Adding a Local Printer .......................................................................... 313
15.3.4. Adding an AppSocket/HP JetDirect printer ............................................. 314
15.3.5. Adding an IPP Printer .......................................................................... 315
15.3.6. Adding an LPD/LPR Host or Printer ...................................................... 316
15.3.7. Adding a Samba (SMB) printer ............................................................. 317
15.3.8. Selecting the Printer Model and Finishing .............................................. 319
15.3.9. Printing a test page .............................................................................. 322
15.3.10. Modifying Existing Printers .................................................................. 323
15.3.11. Additional Resources .......................................................................... 329
VI. Monitoring and Automation 331
16. System Monitoring Tools 333
16.1. Viewing System Processes ............................................................................. 333
16.1.1. Using the ps Command ........................................................................ 333
16.1.2. Using the top Command ....................................................................... 333
16.1.3. Using the System Monitor Tool ............................................................. 334
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16.2. Viewing Memory Usage .................................................................................. 336
16.2.1. Using the free Command ...................................................................... 336
16.2.2. Using the System Monitor Tool ............................................................. 336
16.3. Viewing Block Devices and File Systems ......................................................... 337
16.3.1. Using the lsblk Command ..................................................................... 337
16.3.2. Using the blkid Command .................................................................... 338
16.3.3. Using the partx Command .................................................................... 338
16.3.4. Using the findmnt Command ................................................................ 339
16.3.5. Using the df Command ........................................................................ 340
16.3.6. Using the du Command ........................................................................ 340
16.3.7. Using the System Monitor Tool ............................................................. 341
16.4. Viewing Hardware Information ......................................................................... 341
16.4.1. Using the lspci Command ..................................................................... 341
16.4.2. Using the lsusb Command .................................................................... 342
16.4.3. Using the lspcmcia Command .............................................................. 343
16.4.4. Using the lscpu Command .................................................................... 343
16.5. Monitoring Performance with Net-SNMP .......................................................... 343
16.5.1. Installing Net-SNMP ............................................................................. 344
16.5.2. Running the Net-SNMP Daemon ........................................................... 344
16.5.3. Configuring Net-SNMP ......................................................................... 345
16.5.4. Retrieving Performance Data over SNMP .............................................. 348
16.5.5. Extending Net-SNMP ........................................................................... 351
16.6. Additional Resources ...................................................................................... 356
16.6.1. Installed Documentation ....................................................................... 356
17. Viewing and Managing Log Files 357
17.1. Configuring rsyslog ......................................................................................... 357
17.1.1. Global Directives .................................................................................. 357
17.1.2. Modules .............................................................................................. 357
17.1.3. Rules ................................................................................................... 358
17.1.4. rsyslog Command Line Configuration ................................................... 369
17.2. Locating Log Files .......................................................................................... 369
17.2.1. Configuring logrotate ............................................................................ 369
17.3. Viewing Log Files ........................................................................................... 371
17.4. Adding a Log File ........................................................................................... 374
17.5. Monitoring Log Files ....................................................................................... 374
17.6. Additional Resources ...................................................................................... 375
17.6.1. Installed Documentation ....................................................................... 375
17.6.2. Useful Websites ................................................................................... 375
18. Automating System Tasks 377
18.1. Cron and Anacron .......................................................................................... 377
18.1.1. Starting and Stopping the Service ......................................................... 377
18.1.2. Configuring Anacron Jobs ..................................................................... 377
18.1.3. Configuring Cron Jobs .......................................................................... 379
18.1.4. Controlling Access to Cron ................................................................... 381
18.1.5. Black/White Listing of Cron Jobs ........................................................... 381
18.2. At and Batch .................................................................................................. 381
18.2.1. Configuring At Jobs .............................................................................. 382
18.2.2. Configuring Batch Jobs ........................................................................ 382
18.2.3. Viewing Pending Jobs .......................................................................... 383
18.2.4. Additional Command Line Options ........................................................ 383
18.2.5. Controlling Access to At and Batch ....................................................... 383
18.2.6. Starting and Stopping the Service ......................................................... 383
18.3. Additional Resources ...................................................................................... 384
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