Debian Administration Training Course

Debian Distribution

Introduction to Debian

• Selecting a Debian version
• Accessing Debian support and assistance
• The Debian community

Console fundamentals

• The shell prompt
• The shell prompt within the X environment
• Root account management and root shell prompts (su, sudo, executing programs as root under X)
• GUI-based system administration tools
• Virtual consoles
• Exiting the command prompt
• Shutting down the system
• Restoring a functional console
• Recommended additional packages for beginners
• Creating additional user accounts
• Configuring sudo

The filesystem

• Filesystem permissions
• Managing permissions for newly created files using umask
• Group-based permissions
• Timestamps
• Symlinks and hard links
• Named pipes (FIFOs)
• Sockets
• Device files
• Special device files
• procfs and sysfs

Midnight Commander (MC)

• Customizing MC
• Launching MC
• File management features in MC
• Command-line shortcuts in MC
• The built-in editor in MC
• The built-in viewer in MC
• Auto-start capabilities of MC
• MC's FTP virtual filesystem

Basic Unix-like work environment

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

Simple 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 utilities
• 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 precautions
• Managing continuous upgrades
• Basics of the Debian archive
• Package dependencies
• The workflow of package management
• Initial response to package management issues

Basic package management operations

• Comparison of apt-get/apt-cache vs. aptitude
• Basic command-line package management operations
• Interactive usage of aptitude
• Key bindings in aptitude
• Package views in aptitude
• Search method options in aptitude
• The aptitude regex formula
• Dependency resolution in aptitude
• Package activity logs

Examples of aptitude operations

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

Advanced package management operations

• Advanced command-line package management operations
• Verifying installed package files
• Mitigating package issues
• Searching package metadata

Internals of Debian package management

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

Recovering from a broken system

• Incompatibility with old user configurations
• Conflicts from overlapping files between packages
• Repairing broken package scripts
• Rescue procedures using the dpkg command
• Restoring package selection data

Tips for package management

• Selecting Debian packages
• Using packages from mixed archive sources
• Adjusting candidate versions
• Updates and Backports
• Automatic download and upgrade of packages
• Limiting APT download bandwidth
• Emergency downgrading
• Identifying package uploaders
• The equivs package
• Porting packages to stable systems
• Using a proxy server for APT
• Setting up a small public package archive
• 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
• Understanding runlevels
• Configuring runlevels
• Runlevel management examples
• Default parameters for init scripts
• Hostname configuration
• Filesystem setup
• 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 information
• Creating strong passwords
• Generating 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 rules
• Other access control mechanisms
• Using sudo
• SELinux and AppArmor
• Restricting access to server services
• Authentication security
• Secure password transmission 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-based network configuration tools

Low-level network configuration

• Iproute2 commands
• Safe low-level network operations

Network optimization

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

Netfilter infrastructure

Network applications

The mail system

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

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

• Overview of exim4
• Basic MUA usage - Mutt

Mail Delivery Agent (MDA) with filters

• maildrop configuration
• procmail configuration
• Redelivering mbox contents

POP3/IMAP4 server

Remote access server and utilities (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
• Troubleshooting SSH

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
• Starting the X Window System
• Starting X sessions with gdm
• Customizing X sessions (classic method)
• Customizing X sessions (modern method)
• Connecting remote X clients via SSH
• Secure X terminal access 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 output
• Colorized commands
• Recording editor activities for complex tasks
• Recording graphics from X applications
• Tracking changes in configuration files

Data storage tips

• Disk partition configuration
• Accessing partitions using UUIDs
• 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 symbolic links
• Expanding storage space using aufs

Data encryption tips

• Encrypting removable disks with dm-crypt/LUKS
• Encrypting swap partitions with dm-crypt
• Automatically encrypting files with eCryptfs
• Automatically mounting 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 files or sockets
• Running commands at constant intervals
• Looping commands over files
• Launching programs from the GUI
• Customizing programs to be started
• Terminating processes
• Scheduling one-time tasks
• Scheduling recurring tasks
• Using the Alt-SysRq key

System maintenance tips

• Identifying users on the system
• Warning all users
• Hardware identification
• Hardware configuration
• System and hardware time synchronization
• 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 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 script for system backup
• Script for data backup copying
• 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
• Creating dummy files
• Erasing an entire hard disk
• Erasing unused areas of a hard disk
• Undeleting deleted but still open files
• Searching all hard links
• Invisible disk space consumption

Data security infrastructure

• Key management for GnuPG (signing and encrypting)
• The MD5 checksum