Debian Administration Training Course

Debian Distribution

Introduction to Debian

• Selecting the appropriate Debian version
• Accessing Debian support and assistance
• The Debian community

Console Fundamentals

• Understanding the shell prompt
• Shell prompt behavior within the X environment
• Root account management and root shell access (using su, sudo, and executing programs as root under X)
• GUI-based system administration utilities
• Virtual consoles
• Exiting the command prompt
• Shutting down the system
• Restoring a stable console state
• Recommended additional packages for beginners
• Creating additional user accounts
• Configuring sudo

The Filesystem

• Filesystem permission structures
• Managing permissions for new files via umask
• Group-based permissions
• File timestamps
• Symbolic and hard links
• Named pipes (FIFOs)
• Unix sockets
• Device files
• Special device files
• procfs and sysfs interfaces

Midnight Commander (MC)

• Customizing MC settings
• Launching MC
• Utilizing the MC file manager
• Advanced command-line techniques in MC
• Using the integrated editor in MC
• Using the integrated viewer in MC
• MC auto-start capabilities
• MC's FTP virtual filesystem

The Basic Unix-like Work Environment

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

The Simple Shell Command

• Command execution and environment variables
• "$LANG" variable
• "$PATH" variable
• "$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 expressions
• Global substitution using regular expressions
• Extracting data from text file tables
• Script snippets for piping commands

Debian Package Management

Prerequisites for Debian Package Management

• Package configuration
• Basic safety measures
• Managing continuous upgrades
• Debian archive fundamentals
• Package dependencies
• Package management workflow
• Initial steps for resolving package management issues

Basic Package Management Operations

• Comparing apt-get/apt-cache with aptitude
• Executing basic package management via the command line
• Interactive usage of aptitude
• aptitude key bindings
• Package views in aptitude
• Search options in aptitude
• aptitude regular expression formulas
• Dependency resolution in aptitude
• Package activity logs

aptitude Operation Examples

• Listing packages using regex matching on names
• Browsing with regex matching
• Permanently purging removed packages
• Organizing auto/manual install status
• System-wide upgrades

Advanced Package Management Operations

• Advanced package management via command line
• Verifying installed package files
• Preventative measures for package issues
• Searching package metadata

Internals of Debian Package Management

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

Recovery from a Broken System

• Issues with old user configurations
• Conflicts from overlapping files in different packages
• Correcting broken package scripts
• Rescue operations using dpkg
• Restoring package selection data

Package Management Tips

• Selecting the right Debian packages
• Packages from mixed archive sources
• Adjusting candidate versions
• Handling Updates and Backports
• Automating package downloads and upgrades
• Limiting APT download bandwidth
• Emergency downgrades
• Identifying package uploaders
• The equivs package
• Porting packages to stable systems
• APT proxy servers
• Setting up small public package archives
• Recording and copying system configurations
• Converting or installing alien binary packages
• Extracting packages without dpkg
• Further reading on package management

System Initialization

• Overview of the bootstrapping process
• BIOS, boot loaders, and mini-Debian systems
• The concept of runlevels
• Configuring runlevels
• Example runlevel management
• Default parameters for init scripts
• Hostname configuration
• Filesystem mounts
• Network interface initialization
• Network service initialization
• System messages
• Kernel messages
• The udev system
• Kernel module initialization

Authentication and Security

• Standard Unix authentication
• Managing account and password details
• Crafting strong passwords
• Creating encrypted passwords
• PAM and NSS
• Configuration files used by PAM and NSS
• Modern centralized system management
• Why GNU su does not support the wheel group
• Enforcing stricter password policies
• Additional access controls
• Using sudo
• SELinux and AppArmor
• Restricting access to specific server services
• Authentication security
• Securing passwords over the Internet
• Secure Shell (SSH)
• Additional Internet security measures
• Securing the root password

Network Setup

Basic Network Infrastructure

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

Modern Network Configuration for Desktops

• GUI network configuration tools

Low-Level Network Configuration

• Iproute2 commands
• Safe low-level network operations

Network Optimization

• Finding the optimal MTU
• Configuring MTU
• WAN TCP optimization

Netfilter Infrastructure

Network Applications

The Mail System

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

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

• Overview of exim4
• Basic MUA: 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
• Handling non-standard SSH clients
• Configuring ssh-agent
• Shutting down remote systems via SSH
• SSH troubleshooting

Other Network Application Servers

Other Network Application Clients

Diagnosing System Daemons

The X Window System

• Setting up the desktop environment
• Server-client relationships
• The X server
• Launching the X Window System
• Starting X sessions with gdm
• Customizing X sessions (traditional method)
• Customizing X sessions (modern method)
• Connecting remote X clients via SSH
• Securing X terminals over the Internet
• X 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 analyzers
• Cleanly recording shell activities
• Customizing text data display
• Customizing time and date display
• Colorized shell echo
• Colorized commands
• Recording editor activities for complex repeats
• Recording X application graphics
• Tracking changes in configuration files

Data Storage Tips

• Disk partition configuration
• Accessing partitions using UUID
• Filesystem configuration
• Filesystem creation and integrity checks
• Optimizing filesystems via mount options
• Optimizing filesystems via superblock
• Hard disk optimization
• Predicting hard disk failures using SMART
• Expanding storage space via LVM
• Expanding storage space by mounting additional partitions
• Expanding storage space using symlinks
• Expanding storage space using aufs

Data Encryption Tips

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

Monitoring, Controlling, and Starting Program Activities

• Timing processes
• Scheduling priorities
• The ps command
• The top command
• Listing files opened by a process
• Tracing program activities
• Identifying processes using files or sockets
• Repeating commands at constant intervals
• Repeating commands in loops over files
• Launching programs from the GUI
• Customizing programs to start
• Terminating processes
• One-time task scheduling
• Regular task scheduling
• Alt-SysRq key

System Maintenance Tips

• Identifying active users
• Warning all users
• Hardware identification
• Hardware configuration
• System and hardware time synchronization
• Terminal configuration
• Sound infrastructure
• Disabling screensavers
• Disabling beep sounds
• Memory usage analysis
• System security and integrity checks

The Kernel

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

Virtualized Systems

• Virtualization tools
• Virtualization workflow
• Mounting virtual disk image files
• Chroot systems
• Multiple desktop systems

Data Management

Sharing, Copying, and Archiving

• Archive and compression tools
• Copy and synchronization tools
• Archiving idioms
• Copying idioms
• File selection idioms
• Backup and recovery
• Backup utility suites
• Example system backup script
• Data backup copy script
• Removable storage devices
• Sharing data via network
• Archive media

Binary Data

• Viewing and editing binary data
• Manipulating files without mounting disks
• Data redundancy
• Data file recovery and forensic analysis
• Splitting large files
• Clearing file contents
• Dummy files
• Erasing an entire hard disk
• Erasing unused hard disk areas
• Undeleting open but deleted files
• Finding all hardlinks
• Invisible disk space consumption

Data Security Infrastructure

• GnuPG key management (signing and encryption)
• MD5 checksums