Debian Administration Training Course

Debian Distribution

What is Debian?

• Choosing the right Debian version
• Debian support and resources
• The Debian community

Console fundamentals

• Understanding the shell prompt
• The shell prompt in an X environment
• The root account and root shell prompt (using su, sudo, and running programs as root under X)
• GUI system administration tools
• Virtual consoles
• Exiting the command prompt
• Shutting down the system properly
• Recovering a malfunctioning console
• Recommended packages for beginners
• Setting up an additional user account
• Configuring sudo

The filesystem

• Filesystem permissions
• Controlling permissions for new files: umask
• Permissions for user groups (group)
• Understanding timestamps
• Hard and symbolic links
• Named pipes (FIFOs)
• Sockets
• Device files
• Special device files
• Understanding procfs and sysfs

Midnight Commander (MC)

• Customizing MC
• Launching MC
• Using the file manager in MC
• Command-line techniques within MC
• Using the internal editor in MC
• Using the internal viewer in MC
• MC auto-start features
• MC's FTP virtual filesystem

The basic Unix-like work environment

• The login shell
• Customizing bash
• Using special key strokes
• Using the pager
• Setting a default text editor
• Exiting vim
• Recording shell activities
• Essential Unix commands

The simple shell command

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

Unix-like text processing

• Unix text tools
• Regular expressions
• Replacement expressions
• Global substitution with 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
• Navigating continuous upgrades
• Basics of the Debian archive
• Understanding package dependencies
• The lifecycle of package management events
• Initial steps for resolving package management issues

Basic package management operations

• Comparing apt-get/apt-cache with aptitude
• Performing basic package management operations via the command line
• Interactive use of aptitude
• Key bindings in aptitude
• Package views in aptitude
• Search options in aptitude
• Using aptitude regex formulas
• Dependency resolution with aptitude
• Reviewing package activity logs

Examples of aptitude operations

• Listing packages using regex matching on package names
• Browsing using regex matching
• Permanently purging removed packages
• Managing auto/manual installation status
• Performing a system-wide upgrade

Advanced package management operations

• Advanced operations via the command line
• Verifying installed package files
• Protecting against package issues
• Searching package metadata

Debian package management internals

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

Recovery from a broken system

• Handling incompatibilities with old user configurations
• Resolving overlaps between different packages
• Fixing broken package scripts
• Rescuing with the dpkg command
• Recovering package selection data

Tips for package management

• Selecting Debian packages effectively
• Managing packages from mixed archive sources
• Adjusting candidate versions
• Updates and Backports
• Automating package downloads and upgrades
• Limiting download bandwidth for APT
• Emergency downgrading
• Identifying package uploaders
• Using the equivs package
• Porting packages to stable systems
• Configuring a proxy server for APT
• Using small public package archives
• Recording and copying system configurations
• Converting or installing alien binary packages
• Extracting packages without dpkg
• Further reading on package management

The system initialization

• Overview of the bootstrap process
• BIOS, boot loaders, and mini-Debian systems
• Understanding runlevels
• Configuring runlevels
• Examples of runlevel management
• Default parameters for each init script
• Setting the hostname
• Filesystem configuration during boot
• Initializing network interfaces
• Initializing network services
• System messages
• Kernel messages
• The udev system
• Initializing kernel modules

Authentication and Security

• Standard Unix authentication
• Managing account and password information
• Creating strong passwords
• Creating encrypted passwords
• Understanding PAM and NSS
• Configuration files used by PAM and NSS
• Modern centralized system management
• Why GNU su does not support the wheel group
• Implementing stricter password rules
• Other access control mechanisms
• Using sudo
• SELinux and AppArmor
• Restricting access to specific server services
• Securing authentication processes
• Securing passwords over the Internet
• Secure Shell (SSH)
• Additional security measures for Internet exposure
• Securing the root password

Network setup

The basic network infrastructure

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

Modern network configuration for desktop

• GUI network configuration tools

Low-level network configuration

• Using iproute2 commands
• Safely performing 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 strategies for workstations

Mail transport agent (MTA) and Mail user agent (MUA)

• Overview of exim4
• Basic MUA - Mutt

Mail delivery agent (MDA) with filter

• Configuring maildrop
• Configuring procmail
• Redelivering mbox contents

POP3/IMAP4 server

The remote access server and utility (SSH)

• SSH basics
• Port forwarding for SMTP/POP3 tunneling
• Connecting without remote passwords
• Managing compatibility with other SSH clients
• Setting up 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
• The server/client relationship
• The X server
• Starting the X Window System
• Starting an X session with gdm
• Customizing the X session (classic method)
• Customizing the X session (new method)
• Connecting a remote X client 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 repetitions
• Recording the graphical image of an X application
• Recording changes in configuration files

Data storage tips

• Disk partition configuration
• Accessing partitions using UUID
• Filesystem configuration
• Creating and checking filesystem integrity
• Optimizing filesystems via mount options
• Optimizing filesystems via superblock
• Hard disk optimization
• Using SMART to predict hard disk failure
• Expanding usable storage space via LVM
• Expanding usable storage space by mounting another partition
• Expanding usable storage space using symlinks
• Expanding usable 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 a process
• Setting scheduling priorities
• Using the ps command
• Using the top command
• Listing files opened by a process
• Tracing program activities
• Identifying processes using files or sockets
• Repeating a command at constant intervals
• Repeating a command in a loop over files
• Starting a program from the GUI
• Customizing program startup
• Killing a process
• Scheduling one-time tasks
• Scheduling recurring tasks
• Using the Alt-SysRq key

System maintenance tips

• Checking who is logged into the system
• Notifying all users
• Hardware identification
• Hardware configuration
• System and hardware time synchronization
• Terminal configuration
• Audio infrastructure
• Disabling the screen saver
• Disabling beep sounds
• Monitoring memory usage
• Checking system security and integrity

The kernel

• Kernel parameters
• Kernel headers
• Compiling the kernel and related modules
• Compiling the 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
• Managing multiple desktop systems

Data management

Sharing, copying, and archiving

• Archive and compression tools
• Copy and synchronization tools
• Common idioms for archives
• Common idioms for copying
• Idioms for selecting files
• Backup and recovery strategies
• Backup utility suites
• Example script for system backup
• Script for data backup copying
• Using removable storage devices
• Sharing data via 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 parts
• 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 for all hard links
• Identifying invisible disk space consumption

Data security infrastructure

• Key management for GnuPG (signing and encrypting)
• Understanding MD5 sums