Fedora 26: system administrator's guide: deployment, configuration and administration

Description

System Administrator's Guide Table of Contents Preface 1. Target Audience 2. How to Read this Book 3. Document Conventions 3.1. Typographic Conventions 3.2. Pull-quote Conventions 3.3. Notes and Warnings 4. We Need Feedback! 5. Acknowledgments Part I. Basic System Configuration Chapter 1. Opening Graphical Applications 1.1. Opening graphical applications from the command line 1.2.  Launching Applications with Alt+F2 1.3. Launching applications from the Desktop Menu 1.3.1. Using GNOME menus 1.3.2.  Using KDE menus 1.3.3. Using menus in LXDE, MATE, and XFCE Chapter 2. System Locale and Keyboard Configuration 2.1. Setting the System Locale 2.1.1. Displaying the Current Status 2.1.2. Listing Available Locales 2.1.3. Setting the Locale 2.2. Changing the Keyboard Layout 2.2.1. Displaying the Current Settings 2.2.2. Listing Available Keymaps 2.2.3. Setting the Keymap 2.3. Additional Resources Chapter 3. Configuring the Date and Time 3.1. Using the timedatectl Command 3.1.1. Displaying the Current Date and Time 3.1.2. Changing the Current Time 3.1.3. Changing the Current Date 3.1.4. Changing the Time Zone 3.1.5. Synchronizing the System Clock with a Remote Server 3.2. Using the date Command 3.2.1. Displaying the Current Date and Time 3.2.2. Changing the Current Time 3.2.3. Changing the Current Date 3.3. Using the hwclock Command 3.3.1. Displaying the Current Date and Time 3.3.2. Setting the Date and Time 3.3.3. Synchronizing the Date and Time 3.4. Additional Resources Chapter 4. Managing Users and Groups 4.1. Introduction to Users and Groups 4.1.1. User Private Groups 4.1.2. Shadow Passwords 4.2. Managing Users in a Graphical Environment 4.2.1. Using the Users Settings Tool 4.3. Using Command Line Tools 4.3.1. Adding a New User 4.3.2. Adding a New Group 4.3.3. Enabling Password Aging 4.3.4. Enabling Automatic Logouts 4.3.5. Creating Group Directories 4.4. Additional Resources Chapter 5. Gaining Privileges 5.1. The su Command 5.2. The sudo Command 5.3. Additional Resources Part II. Package Management Chapter 6. DNF 6.1. Checking For and Updating Packages 6.1.1. Checking For Updates 6.1.2. Updating Packages 6.1.3. Preserving Configuration File Changes 6.2. Packages and Package Groups 6.2.1. Searching Packages 6.2.2. Listing Packages 6.2.3. Displaying Package Information 6.2.4. Installing Packages 6.2.5. Removing Packages 6.2.6. Working with Transaction History 6.3. Configuring DNF and DNF Repositories 6.3.1. Setting [main] Options 6.3.2. Setting [repository] Options 6.3.3. Using DNF Variables 6.4. Viewing the Current Configuration 6.5. Adding, Enabling, and Disabling a DNF Repository 6.6. Additional Resources Part III. Infrastructure Services Chapter 7. Services and Daemons 7.1. Configuring Services 7.1.1. Enabling the Service 7.1.2. Disabling the Service 7.2. Running Services 7.2.1. Checking the Service Status 7.2.2. Running the Service 7.2.3. Stopping the Service 7.2.4. Restarting the Service 7.3. Additional Resources 7.3.1. Installed Documentation 7.3.2. Related Books Chapter 8. OpenSSH 8.1. The SSH Protocol 8.1.1. Why Use SSH? 8.1.2. Main Features 8.1.3. Protocol Versions 8.1.4. Event Sequence of an SSH Connection 8.1.4.1. Transport Layer 8.1.4.2. Authentication 8.1.4.3. Channels 8.2. Configuring OpenSSH 8.2.1. Configuration Files 8.2.2. Starting an OpenSSH Server 8.2.3. Requiring SSH for Remote Connections 8.2.4. Using Key-based Authentication 8.2.4.1. Generating Key Pairs 8.2.4.2. Configuring ssh-agent 8.3. Using OpenSSH Certificate Authentication 8.3.1. Introduction to SSH Certificates 8.3.2. Support for SSH Certificates 8.3.3. Creating SSH CA Certificate Signing Keys 8.3.4. Distributing and Trusting SSH CA Public Keys 8.3.5. Creating SSH Certificates 8.3.5.1. Creating SSH Certificates to Authenticate Hosts 8.3.5.2. Creating SSH Certificates for Authenticating Users 8.3.6. Signing an SSH Certificate Using a PKCS#11 Token 8.3.7. Viewing an SSH CA Certificate 8.3.8. Revoking an SSH CA Certificate 8.4. OpenSSH Clients 8.4.1. Using the ssh Utility 8.4.2. Using the scp Utility 8.4.3. Using the sftp Utility 8.5. More Than a Secure Shell 8.5.1. X11 Forwarding 8.5.2. Port Forwarding 8.6. Additional Resources Chapter 9. TigerVNC 9.1. VNC Server 9.1.1. Installing VNC Server 9.1.2. Configuring VNC Server 9.1.2.1. Configuring VNC Server for Two Users 9.1.3. Starting VNC Server 9.1.3.1. Configuring VNC Server for Two Users and Two Different Displays 9.1.4. Terminating a VNC Session 9.2. VNC Viewer 9.2.1. Installing VNC Viewer 9.2.2. Connecting to VNC Server 9.2.2.1. Configuring the Firewall for VNC 9.2.3. Connecting to VNC Server Using SSH 9.3. Additional Resources Part IV. Servers Chapter 10. Web Servers 10.1. The Apache HTTP Server 10.1.1. Notable Changes 10.1.2. Updating the Configuration 10.1.3. Running the httpd Service 10.1.3.1. Starting the Service 10.1.3.2. Stopping the Service 10.1.3.3. Restarting the Service 10.1.3.4. Verifying the Service Status 10.1.4. Editing the Configuration Files 10.1.4.1. Common httpd.conf Directives 10.1.4.2. Common ssl.conf Directives 10.1.4.3. Common Multi-Processing Module Directives 10.1.5. Working with Modules 10.1.5.1. Loading a Module 10.1.5.2. Writing a Module 10.1.6. Setting Up Virtual Hosts 10.1.7. Setting Up an SSL Server 10.1.7.1. An Overview of Certificates and Security 10.1.7.2. Enabling the mod_ssl Module 10.1.7.3. Enabling and Disabling SSL and TLS in mod_ssl 10.1.7.4. Using an Existing Key and Certificate 10.1.7.5. Generating a New Key and Certificate 10.1.8. Additional Resources Chapter 11. Mail Servers 11.1. Email Protocols 11.1.1. Mail Transport Protocols 11.1.1.1. SMTP 11.1.2. Mail Access Protocols 11.1.2.1. POP 11.1.2.2. IMAP 11.1.2.3. Dovecot 11.2. Email Program Classifications 11.2.1. Mail Transport Agent 11.2.2. Mail Delivery Agent 11.2.3. Mail User Agent 11.3. Mail Transport Agents 11.3.1. Postfix 11.3.1.1. The Default Postfix Installation 11.3.1.2. Basic Postfix Configuration 11.3.1.3. Using Postfix with LDAP 11.3.1.3.1. The /etc/aliases lookup example 11.3.2. Sendmail 11.3.2.1. Purpose and Limitations 11.3.2.2. The Default Sendmail Installation 11.3.2.3. Common Sendmail Configuration Changes 11.3.2.4. Masquerading 11.3.2.5. Stopping Spam 11.3.2.6. Using Sendmail with LDAP 11.3.3. Fetchmail 11.3.3.1. Fetchmail Configuration Options 11.3.3.2. Global Options 11.3.3.3. Server Options 11.3.3.4. User Options 11.3.3.5. Fetchmail Command Options 11.3.3.6. Informational or Debugging Options 11.3.3.7. Special Options 11.3.4. Mail Transport Agent (MTA) Configuration 11.4. Mail Delivery Agents 11.4.1. Procmail Configuration 11.4.2. Procmail Recipes 11.4.2.1. Delivering vs. Non-Delivering Recipes 11.4.2.2. Flags 11.4.2.3. Specifying a Local Lockfile 11.4.2.4. Special Conditions and Actions 11.4.2.5. Recipe Examples 11.4.2.6. Spam Filters 11.5. Mail User Agents 11.5.1. Securing Communication 11.5.1.1. Secure Email Clients 11.5.1.2. Securing Email Client Communications 11.6. Additional Resources 11.6.1. Installed Documentation 11.6.2. Useful Websites 11.6.3. Related Books Chapter 12. Directory Servers 12.1. OpenLDAP 12.1.1. Introduction to LDAP 12.1.1.1. LDAP Terminology 12.1.1.2. OpenLDAP Features 12.1.1.3. OpenLDAP Server Setup 12.1.2. Installing the OpenLDAP Suite 12.1.2.1. Overview of OpenLDAP Server Utilities 12.1.2.2. Overview of OpenLDAP Client Utilities 12.1.2.3. Overview of Common LDAP Client Applications 12.1.3. Configuring an OpenLDAP Server 12.1.3.1. Changing the Global Configuration 12.1.3.2. Changing the Database-Specific Configuration 12.1.3.3. Extending Schema 12.1.3.4. Establishing a Secure Connection 12.1.3.5. Setting Up Replication 12.1.3.6. Loading Modules and Backends 12.1.4. SELinux Policy for Applications Using LDAP 12.1.5. Running an OpenLDAP Server 12.1.5.1. Starting the Service 12.1.5.2. Stopping the Service 12.1.5.3. Restarting the Service 12.1.5.4. Verifying the Service Status 12.1.6. Configuring a System to Authenticate Using OpenLDAP 12.1.6.1. Migrating Old Authentication Information to LDAP Format 12.1.7. Additional Resources 12.1.8. Related Books Chapter 13. File and Print Servers 13.1. Samba 13.1.1. Introduction to Samba 13.1.2. Samba Daemons and Related Services 13.1.3. Connecting to a Samba Share 13.1.4. Mounting the Share 13.1.5. Configuring a Samba Server 13.1.5.1. Graphical Configuration 13.1.5.2. Command-Line Configuration 13.1.5.3. Encrypted Passwords 13.1.6. Starting and Stopping Samba 13.1.7. Samba Server Types and the smb.conf File 13.1.7.1. Stand-alone Server 13.1.7.2. Domain Member Server 13.1.7.3. Domain Controller 13.1.8. Samba Security Modes 13.1.8.1. User-Level Security 13.1.8.2. Share-Level Security 13.1.9. Samba Account Information Databases 13.1.10. Samba Network Browsing 13.1.10.1. Domain Browsing 13.1.10.2. WINS (Windows Internet Name Server) 13.1.11. Samba with CUPS Printing Support 13.1.11.1. Simple smb.conf Settings 13.1.12. Samba Distribution Programs 13.1.13. Additional Resources 13.2. FTP 13.2.1. The File Transfer Protocol 13.2.1.1. Multiple Ports, Multiple Modes 13.2.2. FTP Servers 13.2.2.1.  vsftpd 13.2.3. Files Installed with vsftpd 13.2.4. Starting and Stopping vsftpd 13.2.4.1. Starting Multiple Copies of vsftpd 13.2.5.  vsftpd Configuration Options 13.2.5.1. Daemon Options 13.2.5.2. Log In Options and Access Controls 13.2.5.3. Anonymous User Options 13.2.5.4. Local User Options 13.2.5.5. Directory Options 13.2.5.6. File Transfer Options 13.2.5.7. Logging Options 13.2.5.8. Network Options 13.2.6. Additional Resources 13.2.6.1. Installed Documentation 13.2.6.2. Useful Websites 13.3. Printer Configuration 13.3.1. Starting the Printers Configuration Tool 13.3.2. Starting Printer Setup 13.3.3. Adding a Local Printer 13.3.4. Adding an AppSocket/HP JetDirect printer 13.3.5. Adding an IPP Printer 13.3.6. Adding an LPD/LPR Host or Printer 13.3.7. Adding a Samba (SMB) printer 13.3.8. Selecting the Printer Model and Finishing 13.3.9. Printing a Test Page 13.3.10. Modifying Existing Printers 13.3.10.1. The Settings Page 13.3.10.2. The Policies Page 13.3.10.2.1. Sharing Printers 13.3.10.2.2. The Access Control Page 13.3.10.2.3. The Printer Options Page 13.3.10.2.4. Job Options Page 13.3.10.2.5. Ink/Toner Levels Page 13.3.10.3. Managing Print Jobs 13.3.11. Additional Resources 13.3.11.1. Installed Documentation 13.3.11.2. Useful Websites Chapter 14. Configuring NTP Using the chrony Suite 14.1. Introduction to the chrony Suite 14.1.1. Differences Between ntpd and chronyd 14.1.2. Choosing Between NTP Daemons 14.2. Understanding chrony and Its Configuration 14.2.1. Understanding chronyd 14.2.2. Understanding chronyc 14.2.3. Understanding the chrony Configuration Commands 14.2.4. Security with chronyc 14.3. Using chrony 14.3.1. Installing chrony 14.3.2. Checking the Status of chronyd 14.3.3. Starting chronyd 14.3.4. Stopping chronyd 14.3.5. Checking if chrony is Synchronized 14.3.5.1. Checking chrony Tracking 14.3.5.2. Checking chrony Sources 14.3.5.3. Checking chrony Source Statistics 14.3.6. Manually Adjusting the System Clock 14.4. Setting Up chrony for Different Environments 14.4.1. Setting Up chrony for a System Which is Infrequently Connected 14.4.2. Setting Up chrony for a System in an Isolated Network 14.5. Using chronyc 14.5.1. Using chronyc to Control chronyd 14.5.2. Using chronyc for Remote Administration 14.6. Additional Resources 14.6.1. Installed Documentation 14.6.2. Online Documentation Chapter 15. Configuring NTP Using ntpd 15.1. Introduction to NTP 15.2. NTP Strata 15.3. Understanding NTP 15.4. Understanding the Drift File 15.5. UTC, Timezones, and DST 15.6. Authentication Options for NTP 15.7. Managing the Time on Virtual Machines 15.8. Understanding Leap Seconds 15.9. Understanding the ntpd Configuration File 15.10. Understanding the ntpd Sysconfig File 15.11. Disabling chrony 15.12. Checking if the NTP Daemon is Installed 15.13. Installing the NTP Daemon (ntpd) 15.14. Checking the Status of NTP 15.15. Configure the Firewall to Allow Incoming NTP Packets 15.15.1. Change the Firewall Settings 15.15.2. Open Ports in the Firewall for NTP Packets 15.16. Configure ntpdate Servers 15.17. Configure NTP 15.17.1. Configure Access Control to an NTP Service 15.17.2. Configure Rate Limiting Access to an NTP Service 15.17.3. Adding a Peer Address 15.17.4. Adding a Server Address 15.17.5. Adding a Broadcast or Multicast Server Address 15.17.6. Adding a Manycast Client Address 15.17.7. Adding a Broadcast Client Address 15.17.8. Adding a Manycast Server Address 15.17.9. Adding a Multicast Client Address 15.17.10. Configuring the Burst Option 15.17.11. Configuring the iburst Option 15.17.12. Configuring Symmetric Authentication Using a Key 15.17.13. Configuring the Poll Interval 15.17.14. Configuring Server Preference 15.17.15. Configuring the Time-to-Live for NTP Packets 15.17.16. Configuring the NTP Version to Use 15.18. Configuring the Hardware Clock Update 15.19. Configuring Clock Sources 15.20. Additional Resources 15.20.1. Installed Documentation 15.20.2. Useful Websites Chapter 16. Configuring PTP Using ptp4l 16.1. Introduction to PTP 16.1.1. Understanding PTP 16.1.2. Advantages of PTP 16.2. Using PTP 16.2.1. Checking for Driver and Hardware Support 16.2.2. Installing PTP 16.2.3. Starting ptp4l 16.2.3.1. Selecting a Delay Measurement Mechanism 16.3. Specifying a Configuration File 16.4. Using the PTP Management Client 16.5. Synchronizing the Clocks 16.6. Verifying Time Synchronization 16.7. Serving PTP Time with NTP 16.8. Serving NTP Time with PTP 16.9. Synchronize to PTP or NTP Time Using timemaster 16.9.1. Starting timemaster as a Service 16.9.2. Understanding the timemaster Configuration File 16.9.3. Configuring timemaster Options 16.10. Improving Accuracy 16.11. Additional Resources 16.11.1. Installed Documentation 16.11.2. Useful Websites Part V. Monitoring and Automation Chapter 17. System Monitoring Tools 17.1. Viewing System Processes 17.1.1. Using the ps Command 17.1.2. Using the top Command 17.1.3. Using the System Monitor Tool 17.2. Viewing Memory Usage 17.2.1. Using the free Command 17.2.2. Using the System Monitor Tool 17.3. Viewing CPU Usage 17.3.1. Using the System Monitor Tool 17.4. Viewing Block Devices and File Systems 17.4.1. Using the lsblk Command 17.4.2. Using the blkid Command 17.4.3. Using the partx Command 17.4.4. Using the findmnt Command 17.4.5. Using the df Command 17.4.6. Using the du Command 17.4.7. Using the System Monitor Tool 17.5. Viewing Hardware Information 17.5.1. Using the lspci Command 17.5.2. Using the lsusb Command 17.5.3. Using the lspcmcia Command 17.5.4. Using the lscpu Command 17.6. Monitoring Performance with Net-SNMP 17.6.1. Installing Net-SNMP 17.6.2. Running the Net-SNMP Daemon 17.6.2.1. Starting the Service 17.6.2.2. Stopping the Service 17.6.2.3. Restarting the Service 17.6.3. Configuring Net-SNMP 17.6.3.1. Setting System Information 17.6.3.2. Configuring Authentication 17.6.4. Retrieving Performance Data over SNMP 17.6.4.1. Hardware Configuration 17.6.4.2. CPU and Memory Information 17.6.4.3. File System and Disk Information 17.6.4.4. Network Information 17.6.5. Extending Net-SNMP 17.6.5.1. Extending Net-SNMP with Shell Scripts 17.6.5.2. Extending Net-SNMP with Perl 17.7. Additional Resources 17.7.1. Installed Documentation Chapter 18. Viewing and Managing Log Files 18.1. Locating Log Files 18.2. Basic Configuration of Rsyslog 18.2.1. Filters 18.2.2. Actions 18.2.3. Templates 18.2.4. Global Directives 18.2.5. Log Rotation 18.3. Using the New Configuration Format 18.3.1. Rulesets 18.3.2. Compatibility with syslogd 18.4. Working with Queues in Rsyslog 18.4.1. Defining Queues 18.4.2. Managing Queues 18.5. Configuring rsyslog on a Logging Server 18.5.1. Using The New Template Syntax on a Logging Server 18.6. Using Rsyslog Modules 18.6.1. Importing Text Files 18.6.2. Exporting Messages to a Database 18.6.3. Enabling Encrypted Transport 18.6.4. Using RELP 18.7. Interaction of Rsyslog and Journal 18.8. Structured Logging with Rsyslog 18.8.1. Importing Data from Journal 18.8.2. Filtering Structured Messages 18.8.3. Parsing JSON 18.8.4. Storing Messages in the MongoDB 18.9. Debugging Rsyslog 18.10. Troubleshooting Logging to a Server 18.11. Using the Journal 18.11.1. Viewing Log Files 18.11.2. Access Control 18.11.3. Using The Live View 18.11.4. Filtering Messages 18.11.5. Enabling Persistent Storage 18.12. Managing Log Files in a Graphical Environment 18.12.1. Viewing Log Files 18.12.2. Adding a Log File 18.12.3. Monitoring Log Files 18.13. Additional Resources Chapter 19. Automating System Tasks 19.1. Cron and Anacron 19.1.1. Installing Cron and Anacron 19.1.2. Running the Crond Service 19.1.2.1. Starting and Stopping the Cron Service 19.1.2.2. Stopping the Cron Service 19.1.2.3. Restarting the Cron Service 19.1.3. Configuring Anacron Jobs 19.1.3.1. Examples of Anacron Jobs 19.1.4. Configuring Cron Jobs 19.1.5. Controlling Access to Cron 19.1.6. Black and White Listing of Cron Jobs 19.2. At and Batch 19.2.1. Installing At and Batch 19.2.2. Running the At Service 19.2.2.1. Starting and Stopping the At Service 19.2.2.2. Stopping the At Service 19.2.2.3. Restarting the At Service 19.2.3. Configuring an At Job 19.2.4. Configuring a Batch Job 19.2.5. Viewing Pending Jobs 19.2.6. Additional Command Line Options 19.2.7. Controlling Access to At and Batch 19.3. Additional Resources Chapter 20. OProfile 20.1. Overview of Tools 20.1.1. operf vs. opcontrol 20.2. Using operf 20.2.1. Specifying the Kernel 20.2.2. Setting Events to Monitor 20.2.3. Categorization of Samples 20.3. Configuring OProfile Using Legacy Mode 20.3.1. Specifying the Kernel 20.3.2. Setting Events to Monitor 20.3.2.1. Sampling Rate 20.3.2.2. Unit Masks 20.3.3. Separating Kernel and User-space Profiles 20.4. Starting and Stopping OProfile Using Legacy Mode 20.5. Saving Data in Legacy Mode 20.6. Analyzing the Data 20.6.1. Using opreport 20.6.2. Using opreport on a Single Executable 20.6.3. Getting More Detailed Output on the Modules 20.6.4. Using opannotate 20.7. Understanding the /dev/oprofile/ directory 20.8. Example Usage 20.9. OProfile Support for Java 20.9.1. Profiling Java Code 20.10. Graphical Interface 20.11. OProfile and SystemTap 20.12. Additional Resources Part VI. Kernel, Module and Driver Configuration Chapter 21. Working with the GRUB 2 Boot Loader 21.1. Introduction to GRUB 2 21.2. Configuring the GRUB 2 Boot Loader 21.3. Making Temporary Changes to a GRUB 2 Menu 21.4. Making Persistent Changes to a GRUB 2 Menu Using the grubby Tool 21.5. Customizing the GRUB 2 Configuration File 21.5.1. Changing the Default Boot Entry 21.5.2. Editing a Menu Entry 21.5.3. Adding a new Entry 21.5.4. Creating a Custom Menu 21.6. GRUB 2 Password Protection 21.6.1. Setting Up Users and Password Protection, Specifying Menu Entries 21.6.2. Password Encryption 21.7. Reinstalling GRUB 2 21.7.1. Reinstalling GRUB 2 on BIOS-Based Machines 21.7.2. Reinstalling GRUB 2 on UEFI-Based Machines 21.7.3. Resetting and Reinstalling GRUB 2 21.8. GRUB 2 over a Serial Console 21.8.1. Configuring the GRUB 2 Menu 21.8.2. Using screen to Connect to the Serial Console 21.9. Terminal Menu Editing During Boot 21.9.1. Booting to Rescue Mode 21.9.2. Booting to Emergency Mode 21.9.3. Changing and Resetting the Root Password 21.10. UEFI Secure Boot 21.10.1. UEFI Secure Boot Support in Fedora 21.11. Additional Resources Chapter 22. Manually Upgrading the Kernel 22.1. Overview of Kernel Packages 22.2. Preparing to Upgrade 22.3. Downloading the Upgraded Kernel 22.4. Performing the Upgrade 22.5. Verifying the Initial RAM Disk Image 22.6. Verifying the Boot Loader 22.6.1. Configuring the GRUB 2 Boot Loader 22.6.2. Configuring the OS/400 Boot Loader 22.6.3. Configuring the YABOOT Boot Loader Chapter 23. Working with Kernel Modules 23.1. Listing Currently-Loaded Modules 23.2. Displaying Information About a Module 23.3. Loading a Module 23.4. Unloading a Module 23.5. Setting Module Parameters 23.6. Persistent Module Loading 23.7. Signing Kernel Modules for Secure Boot 23.7.1. Prerequisites 23.7.2. Kernel Module Authentication 23.7.2.1. Sources For Public Keys Used To Authenticate Kernel Modules 23.7.2.2.  Kernel Module Authentication Requirements 23.7.3. Generating a Public and Private X.509 Key Pair 23.7.4. Enrolling Public Key on Target System 23.7.4.1. Factory Firmware Image Including Public Key 23.7.4.2. Executable Key Enrollment Image Adding Public Key 23.7.4.3. System Administrator Manually Adding Public Key to the MOK List 23.7.5. Signing Kernel Module with the Private Key 23.7.6. Loading Signed Kernel Module 23.8. Additional Resources Appendix A. RPM A.1. RPM Design Goals A.2. Using RPM A.2.1. Installing and Upgrading Packages A.2.1.1. Replacing Already-Installed Packages A.2.1.2. Resolving File Conflicts A.2.1.3. Satisfying Unresolved Dependencies A.2.1.4. Preserving Changes in Configuration Files A.2.2. Uninstalling Packages A.2.3. Freshening Packages A.2.4. Querying Packages A.2.5. Verifying Packages A.3. Finding and Verifying RPM Packages A.3.1. Finding RPM Packages A.3.2. Checking Package Signatures A.3.2.1. Importing GPG Keys A.4. Common Examples of RPM Usage A.5. Additional Resources Appendix B. Revision History Index