Debian Administration Training Course

Debian Distribution

Introduction to Debian

• Selecting the appropriate Debian version
• Accessing Debian support and resources
• Engaging with the Debian community

Console Fundamentals

• Understanding the shell prompt
• The shell prompt within an X environment
• Root account management and root shell prompt (su, sudo, executing programs as root under X)
• GUI-based system administration utilities
• Virtual console usage
• Exiting the command prompt
• System shutdown procedures
• Restoring a stable console state
• Recommended additional packages for beginners
• Creating additional user accounts
• Configuring sudo

The Filesystem

• Filesystem permission models
• Controlling permissions for new files via umask
• Group-based user permissions
• Timestamp management
• File links
• Named pipes (FIFOs)
• Network sockets
• Device files
• Special device files
• procfs and sysfs interfaces

Midnight Commander (MC)

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

The Basic Unix-like Environment

• The login shell
• Customizing bash
• Special key combinations
• Using 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 patterns
• Global substitution using regular expressions
• Extracting data from tabular text files
• Script snippets for piping commands

Debian Package Management

Prerequisites for Debian Package Management

• Package configuration fundamentals
• Essential precautions
• Managing continuous upgrades
• Basics of the Debian archive
• Package dependencies
• The workflow of package management
• Initial troubleshooting steps for package issues

Basic Package Management Operations

• Comparing apt-get/apt-cache with aptitude
• Basic package management via the command line
• Interactive usage of aptitude
• Key bindings in aptitude
• Package views within aptitude
• Search options in aptitude
• The aptitude regular expression formula
• Dependency resolution in aptitude
• Package activity logging

Examples of aptitude Operations

• Listing packages using regex on names
• Browsing via regex matching
• Completely purging removed packages
• Organizing auto/manual install statuses
• Performing system-wide upgrades

Advanced Package Management Operations

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

Debian Package Management Internals

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

Recovering a Broken System

• Handling incompatibility with old user configurations
• Managing different packages with overlapping files
• Fixing broken package scripts
• Rescue operations using the dpkg command
• Restoring package selection data

Package Management Tips

• Selecting Debian packages
• Sourcing packages from mixed archives
• Adjusting candidate versions
• Managing Updates and Backports
• Automatic package download and upgrade
• Limiting APT download bandwidth
• Emergency package downgrading
• Identifying package uploaders
• Using the equivs package
• Porting packages to stable systems
• Configuring an APT proxy server
• 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 boot strap process
• BIOS, boot loader, and mini-Debian systems
• Understanding runlevels
• Configuring runlevels
• Runlevel management example
• Default parameters for init scripts
• Hostname configuration
• Filesystem initialization
• Network interface setup
• 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 concepts
• 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 security measures for Internet connectivity
• Protecting the root password

Network Setup

Basic Network Infrastructure

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

Modern Desktop Network Configuration

• GUI network configuration tools

Low-Level Network Configuration

• Iproute2 commands
• Safe low-level network operations

Network Optimization

• Determining optimal MTU
• Configuring 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 usage with Mutt

Mail Delivery Agent (MDA) with Filtering

• Configuring maildrop
• Configuring procmail
• 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 relationships
• The X server
• Starting the X Window System
• Starting an X session with gdm
• Customizing the X session (classic method)
• Customizing the X session (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 analysis tools
• 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 graphical output of X applications
• Tracking changes in configuration files

Data Storage Tips

• Disk partitioning
• Accessing partitions via UUID
• Filesystem configuration
• Creating and checking filesystem integrity
• Optimizing filesystems with mount options
• Optimizing filesystems via superblock
• Hard disk optimization
• Predicting hard disk failure with SMART
• Expanding usable storage via LVM
• Expanding usable storage by mounting additional partitions
• Expanding usable storage using symbolic links
• Expanding usable storage 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 specific files or sockets
• Repeating commands at constant intervals
• Looping commands over files
• Launching programs from the GUI
• Customizing programs to start
• Terminating processes
• Scheduling one-time tasks
• Scheduling regular tasks
• Using the Alt-SysRq key

System Maintenance Tips

• Checking who is logged in
• Sending system-wide warnings
• Hardware identification
• Hardware configuration
• System and hardware time synchronization
• Terminal configuration
• Sound infrastructure
• Disabling the screen saver
• 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 workflows
• Mounting virtual disk images
• Chroot systems
• Managing multiple desktop systems

Data Management

Sharing, Copying, and Archiving

• Archive and compression utilities
• Copy and synchronization tools
• Archiving idioms
• Copying idioms
• File selection idioms
• Backup and recovery strategies
• Backup utility suites
• Example script for system backup
• Script for data backup copying
• Removable storage devices
• Sharing data over the 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
• Wiping an entire hard disk
• Erasing unused hard disk areas
• Restoring deleted but open files
• Searching all hard links
• Identifying invisible disk space consumption

Data Security Infrastructure

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