Debian Administration Training Course

Debian Distribution

Introduction to Debian

• Selecting a Debian release
• Debian support and assistance resources
• The Debian community

Console Fundamentals

• Understanding the shell prompt
• The shell prompt within an X environment
• Managing the root account and root shell (su, sudo, running applications as root under X)
• Graphical system administration utilities
• Virtual consoles
• Exiting the command prompt
• Shutting down the system
• Restoring a responsive console
• Recommended packages for beginners
• Creating additional user accounts
• Configuring sudo

The File System

• File system permissions
• Controlling permissions for new files using umask
• Group permissions
• File timestamps
• Symbolic and hard links
• Named pipes (FIFOs)
• Network sockets
• Device files
• Special device files
• procfs and sysfs interfaces

Midnight Commander (MC)

• Customising MC settings
• Launching MC
• Using the file manager in MC
• Command-line shortcuts within MC
• Using the internal editor in MC
• Using the internal viewer in MC
• MC auto-start features
• MC's FTP virtual file system

The Fundamental Unix-like Work Environment

• The login shell
• Customising bash
• Special key combinations
• Using the pager
• Setting a default text editor
• Exiting vim
• Logging shell activities
• Essential Unix commands

Basic Shell Commands

• Command execution and environment variables
• The "$LANG" variable
• The "$PATH" variable
• The "$HOME" variable
• Command-line options
• Shell globbing
• Command return values
• Common command sequences and shell redirection
• Command aliases

Unix-like Text Processing

• Unix text manipulation tools
• Regular expressions
• Replacement patterns
• Global substitution using regular expressions
• Extracting data from text-based tables
• Script snippets for piping commands

Debian Package Management

Prerequisites for Debian Package Management

• Package configuration
• Basic safety precautions
• Managing continuous upgrades
• Debian archive fundamentals
• Package dependencies
• The package management workflow
• Initial troubleshooting for package issues

Basic Package Management Operations

• Comparison of apt-get/apt-cache vs. aptitude
• Essential package operations via command line
• Interactive use of aptitude
• aptitude key bindings
• Package views in aptitude
• Search options with aptitude
• Using aptitude regular expressions
• Dependency resolution in aptitude
• Package activity logs

Examples of aptitude Operations

• Listing packages with regular expression name matching
• Browsing using regular expression matches
• Completely purging removed packages
• Managing auto/manual install statuses
• Performing system-wide upgrades

Advanced Package Management Operations

• Advanced command-line package operations
• Verifying installed package files
• Protecting against package conflicts
• Searching package metadata

Debian Package Management Internals

• Archive metadata structure
• Top-level "Release" file and authenticity verification
• Archive-level "Release" files
• Fetching package metadata
• Package state in APT
• Package state in aptitude
• Local cache of downloaded packages
• Debian package file naming conventions
• The dpkg command
• The update-alternatives command
• The dpkg-statoverride command
• The dpkg-divert command

Recovering from a Broken System

• Handling incompatibility with legacy user configurations
• Resolving file overlaps between different packages
• Fixing broken package scripts
• Rescue operations using dpkg
• Restoring package selection data

Tips for Package Management

• Selecting appropriate Debian packages
• Using packages from mixed archive sources
• Adjusting candidate versions
• Updates and Backports
• Automatic downloading and upgrading of packages
• Limiting APT download bandwidth
• Emergency downgrading procedures
• Identifying package uploaders
• The equivs package utility
• Porting packages to the stable release
• Configuring a proxy server for APT
• Creating a small public package archive
• Recording and copying system configurations
• Converting or installing alien binary packages
• Extracting package contents without dpkg
• Further reading on package management

System Initialisation

• Overview of the bootstrapping process
• BIOS, boot loader, and the mini-Debian system
• Understanding runlevels
• Configuring runlevels
• Runlevel management examples
• Default parameters for init scripts
• Hostname configuration
• File system mounting during boot
• Network interface initialisation
• Network service initialisation
• System messaging
• Kernel messaging
• The udev system
• Kernel module initialisation

Authentication and Security

• Standard Unix authentication
• Managing account and password data
• Creating strong passwords
• Generating encrypted passwords
• PAM and NSS frameworks
• Configuration files used by PAM and NSS
• Modern centralised system management
• Why GNU su does not support the wheel group
• Enforcing stricter password rules
• Additional access controls
• Sudo configuration
• SELinux and AppArmor
• Restricting access to specific server services
• Authentication security
• Secure password transmission over the internet
• Secure Shell (SSH)
• Additional internet security measures
• Securing the root password

Network Configuration

Basic Network Infrastructure

• Domain names
• Hostname resolution
• Network interface naming
• LAN network address ranges
• Network device support

Modern Network Configuration for Desktops

• GUI-based network configuration tools

Low-Level Network Configuration

• Iproute2 commands
• Safe low-level network operations

Network Optimisation

• Determining the optimal MTU
• Setting MTU values
• WAN TCP optimisation

Netfilter Infrastructure

Network Applications

The Mail System

• Fundamentals of modern mail services
• Mail configuration strategy for workstations

Mail Transport Agent (MTA) and Mail User Agent (MUA)

• Overview of exim4
• Basic MUA usage with Mutt

Mail Delivery Agent (MDA) with Filtering

• Configuring maildrop
• Configuring procmail
• Redelivering mbox contents

POP3/IMAP4 Server

Remote Access Server and Utility (SSH)

• SSH fundamentals
• Port forwarding for SMTP/POP3 tunneling
• Connecting without remote passwords
• Interacting with non-standard SSH clients
• Setting up ssh-agent
• Shutting down the remote system via SSH
• Troubleshooting SSH connections

Other Network Application Servers

Other Network Application Clients

Diagnosing System Daemons

The X Window System

• Setting up the desktop environment
• The server/client relationship
• The X server
• Starting the X Window System
• Starting an X session with gdm
• Customising the X session (traditional method)
• Customising the X session (modern method)
• Connecting a remote X client via SSH
• Secure X terminal access over the internet
• X-based applications
• X office applications
• X utility applications

System Tips

The Screen Program

• Use cases for screen(1)
• Key bindings for the screen command

Data Recording and Presentation

• The log daemon
• Log analysis tools
• Cleanly recording shell activities
• Customising text data display
• Customising time and date display
• Colourised shell output
• Colourised commands
• Recording editor activities for complex repetitions
• Capturing graphics from X applications
• Tracking changes in configuration files

Data Storage Tips

• Disk partitioning configuration
• Accessing partitions using UUIDs
• File system configuration
• Creating and checking file system integrity
• Optimising file systems via mount options
• Optimising file systems via superblock settings
• Hard disk optimisation
• Predicting hard disk failure using SMART
• Expanding storage space with LVM
• Expanding storage by mounting additional partitions
• Expanding storage using symbolic links
• Expanding storage using aufs

Data Encryption Tips

• Encrypting removable disks with dm-crypt/LUKS
• Encrypting swap partitions with dm-crypt
• Automatic file encryption with eCryptfs
• Automatic mounting of eCryptfs

Monitoring, Controlling, and Starting Program Activities

• Timing processes
• Scheduling priority
• The ps command
• The top command
• Listing files opened by a process
• Tracing program activities
• Identifying processes using specific files or sockets
• Repeating a command at constant intervals
• Looping a command over files
• Starting programs from the GUI
• Customising programs to be launched
• Terminating processes
• Scheduling one-time tasks
• Scheduling recurring tasks
• Using the Alt-SysRq key

System Maintenance Tips

• Identifying active users
• Issuing system warnings
• Hardware identification
• Hardware configuration
• System and hardware time synchronisation
• Terminal configuration
• Sound infrastructure
• Disabling the screen saver
• Disabling beep sounds
• Memory usage monitoring
• System security and integrity checks

The Kernel

• Kernel parameters
• Kernel headers
• Compiling the kernel and modules
• Compiling kernel source: Debian standard method
• Compiling module source: Debian standard method
• Non-free hardware drivers

Virtualised Systems

• Virtualisation tools
• Virtualisation workflows
• Mounting virtual disk images
• Chroot environments
• Managing multiple desktop systems

Data Management

Sharing, Copying, and Archiving

• Archive and compression tools
• Copy and synchronisation tools
• Common practices for archiving
• Common practices for copying
• Common practices for file selection
• Backup and recovery strategies
• Backup utility suites
• Example script for system backup
• Example script for data backup
• Removable storage devices
• Sharing data over the network
• Archive media

Binary Data

• Viewing and editing binary data
• Manipulating files without mounting the disk
• Data redundancy
• Data file recovery and forensic analysis
• Splitting large files into smaller chunks
• Clearing file contents
• Creating dummy files
• Wiping an entire hard disk
• Erasing unused areas of a hard disk
• Restoring deleted but still open files
• Finding all hard links
• Invisible disk space consumption

Data Security Infrastructure

• GnuPG key management for signing and encryption
• MD5 checksums