Debian Administration Training Course

Debian Distribution

Understanding Debian

• Selecting a Debian release
• Accessing Debian support and assistance
• Engaging with the Debian community

Console fundamentals

• The shell prompt interface
• Using the shell prompt within X
• Root account management and root shell access (su, sudo, executing programs as root under X)
• GUI-based system administration utilities
• Virtual console management
• Exiting the command prompt
• Shutting down the system properly
• Restoring a functional console
• Recommended additional packages for beginners
• Creating an additional user account
• Configuring sudo

Filesystem architecture

• Filesystem permission structures
• Controlling permissions for new files: umask
• Group-based user permissions
• Timestamp management
• Symbolic and hard links
• Named pipes (FIFOs)
• Sockets
• Device files
• Special device files
• procfs and sysfs interfaces

Midnight Commander (MC)

• Customizing MC settings
• Launching MC
• Utilizing the MC file manager
• Command-line shortcuts in MC
• Using the built-in MC editor
• Using the built-in MC viewer
• MC auto-start capabilities
• MC's FTP virtual filesystem

Foundational Unix-like environment

• The login shell
• Tailoring bash configuration
• Special keystrokes
• The pager utility
• Setting a default text editor
• Exiting vim
• Recording shell session activities
• Essential Unix commands

Basic shell command mechanics

• 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-style text processing

• Unix text utilities
• Regular expressions
• Replacement patterns
• Global substitution using regular expressions
• Extracting data from text file tables
• Script snippets for piping commands

Debian package administration

Prerequisites for Debian package management

• Package configuration
• Essential precautions
• Managing continuous upgrades
• Basics of the Debian archive
• Package dependencies
• Workflow of package management
• Initial steps to resolve package management issues

Core package management tasks

• apt-get/apt-cache vs. aptitude
• Basic package operations via command line
• Interactive aptitude usage
• aptitude key bindings
• Package views in aptitude
• Search options in aptitude
• aptitude regular expression formulas
• aptitude dependency resolution
• Package activity logs

aptitude operation examples

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

Advanced package management tasks

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

Internal mechanisms of Debian package management

• Archive metadata
• Top-level "Release" file 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

Recovering from a compromised system

• Handling old user configuration incompatibilities
• Resolving file overlaps between different packages
• Fixing broken package scripts
• Using dpkg for system rescue
• Restoring package selection data

Package management best practices

• Selecting Debian packages effectively
• Handling packages from mixed archive sources
• Adjusting candidate versions
• Updates and Backports
• Automatic package download and upgrade
• Limiting APT download bandwidth
• Emergency package downgrading
• Identifying package uploaders
• The equivs package
• Porting packages to the stable system
• Using a proxy server for APT
• Small public package archives
• Recording and duplicating system configurations
• Converting or installing foreign binary packages
• Extracting packages without dpkg
• Additional resources for package management

System initialization

• Overview of the boot strap process
• BIOS, boot loader, and mini-Debian system
• Understanding runlevels
• Configuring runlevels
• Runlevel management examples
• Default parameters for each init script
• 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 data
• Creating strong passwords
• Generating encrypted passwords
• PAM and NSS frameworks
• Configuration files for PAM and NSS
• Modern centralized system management
• "Why GNU su does not support the wheel group"
• Strict password policies
• Additional access controls
• sudo usage
• SELinux, 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

Foundational network infrastructure

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

Modern desktop network configuration

• GUI-based network configuration tools

Low-level network configuration

• Iproute2 commands
• Safe low-level network operations

Network optimization

• Determining optimal MTU
• Setting MTU
• WAN TCP optimization

Netfilter infrastructure

Network applications

Mail systems

• Modern mail service fundamentals
• Mail configuration strategy for workstations

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

• Overview of exim4
• Basic MUA - Mutt

Mail delivery agent (MDA) with filtering

• maildrop configuration
• procmail configuration
• Redelivering mbox contents

POP3/IMAP4 servers

Remote access servers and utilities (SSH)

• SSH fundamentals
• Port forwarding for SMTP/POP3 tunneling
• Connecting without remote passwords
• Managing non-standard SSH clients
• Setting up 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 relationship
• The X server
• Launching the X Window System
• Starting an X session with gdm
• Customizing the X session (traditional method)
• Customizing the X session (modern method)
• Connecting a remote X client via SSH
• Secure X terminal access via 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
• Capturing graphical images of X applications
• Tracking changes in configuration files

Data storage tips

• Disk partition configuration
• Accessing partitions using UUID
• Filesystem configuration
• Creating filesystems and checking integrity
• Filesystem optimization via mount options
• Filesystem optimization via superblock
• Hard disk optimization
• Predicting hard disk failure using SMART
• 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

• Removable disk encryption with dm-crypt/LUKS
• Encrypted swap partition with dm-crypt
• Automatically encrypting files with eCryptfs
• Automatically mounting eCryptfs

Monitoring, controlling, and initiating program activities

• Timing a process
• Scheduling priority
• The ps command
• The top command
• Listing files opened by a process
• Tracing program activities
• Identifying processes using files or sockets
• Repeating a command at a constant interval
• Repeating a command by looping over files
• Launching a program from the GUI
• Customizing programs to be started
• Terminating a process
• Scheduling one-time tasks
• Scheduling recurring tasks
• Alt-SysRq key

System maintenance tips

• Checking who is on the system
• Broadcasting warnings to all users
• Hardware identification
• Hardware configuration
• System and hardware time
• Terminal configuration
• Sound infrastructure
• Disabling the screen saver
• Disabling beep sounds
• Memory usage
• System security and integrity checks

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 system
• Multiple desktop systems

Data management

Sharing, copying, and archiving

• Archive and compression tools
• Copy and synchronization tools
• Archive idioms
• Copy 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 into smaller ones
• Clearing file contents
• Creating dummy files
• Erasing an entire hard disk
• Erasing unused areas of a hard disk
• Undeleting deleted but still open files
• Finding all hard links
• Invisible disk space consumption

Data security infrastructure

• Key management for GnuPG (signing and encryption)
• MD5 checksums