Debian Administration Training Course

Debian Distribution

Understanding Debian

• Selecting a Debian version
• Debian support resources and help
• The Debian community

Console Fundamentals

• The shell prompt
• The shell prompt within the X environment
• The root account and root shell prompt (su, sudo, running programs as root in X)
• GUI system administration tools
• Virtual consoles
• Exiting the command prompt
• Shutting down the system
• Restoring a stable console
• Recommended additional packages for beginners
• Creating an extra user account
• sudo configuration

The Filesystem

• Filesystem permissions
• Controlling permissions for newly created files: umask
• Permissions for user groups (group)
• Timestamps
• Links
• Named pipes (FIFOs)
• Sockets
• Device files
• Special device files
• procfs and sysfs

Midnight Commander (MC)

• Customising MC
• Launching MC
• File manager features in MC
• Command-line techniques in MC
• The internal editor in MC
• The internal viewer in MC
• Auto-start capabilities of MC
• MC's FTP virtual filesystem

The Basic Unix-like Work Environment

• The login shell
• Customising bash
• Special key strokes
• The pager
• Setting a default text editor
• Exiting vim
• Recording shell activities
• Basic 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
• Command aliases

Unix-like Text Processing

• Unix text 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 precautions
• Managing continuous upgrades
• Debian archive basics
• Package dependencies
• The flow of events in package management
• Initial responses to package management issues

Basic Package Management Operations

• apt-get/apt-cache vs. aptitude
• Basic package management via the command line
• Interactive use of aptitude
• aptitude key bindings
• Package views in aptitude
• Search method options with aptitude
• The aptitude regular expression formula
• Dependency resolution in aptitude
• Package activity logs

aptitude Operation Examples

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

Advanced Package Management Operations

• Advanced package management via the command line
• Verifying installed package files
• Mitigating package problems
• 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 for APT
• Package state for aptitude
• Local copies of fetched packages
• Debian package file naming
• The dpkg command
• The update-alternatives command
• The dpkg-statoverride command
• The dpkg-divert command

Recovering from a Broken System

• Incompatibility with legacy user configurations
• Conflicting packages with overlapping files
• Fixing broken package scripts
• Rescuing with the dpkg command
• Restoring package selection data

Package Management Tips

• Selecting the right Debian packages
• Packages from mixed archive sources
• Adjusting candidate versions
• Updates and Backports
• Automatic package download and upgrade
• Limiting download bandwidth for APT
• Emergency downgrading
• Identifying package uploaders
• The equivs package
• Porting packages to stable systems
• APT proxy servers
• Small public package archives
• Recording and copying system configurations
• Converting or installing foreign binary packages
• Extracting packages without dpkg
• Further reading on package management

System Initialization

• Overview of the bootstrapping process
• BIOS, boot loader, and mini-Debian systems
• The concept of runlevels
• Configuring runlevels
• Examples of runlevel management
• Default parameters for init scripts
• Hostnames
• The filesystem
• 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 for PAM and NSS
• Modern centralized system management
• "Why GNU su does not support the wheel group"
• Strict password policies
• Other access controls
• sudo
• SELinux, AppArmor
• Restricting access to specific server services
• Authentication security
• Securing passwords over the Internet
• Secure Shell (SSH)
• Additional security measures for Internet connections
• Securing the root password

Network Setup

Basic Network Infrastructure

• Domain names
• Hostname resolution
• Network interface naming
• Network address ranges for LANs
• 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
• 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 - Mutt

Mail Delivery Agent (MDA) with Filters

• maildrop configuration
• procmail configuration
• Redelivering mbox contents

POP3/IMAP4 Servers

Remote Access Server and Utilities (SSH)

• SSH fundamentals
• Port forwarding for SMTP/POP3 tunneling
• Connecting without remote passwords
• Handling foreign 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
• The server/client relationship
• The X server
• Starting the X Window System
• Starting X sessions with gdm
• Customising X sessions (classic method)
• Customising X sessions (modern method)
• Connecting remote X clients via SSH
• Secure 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
• Custom text data display
• Custom time and date display
• Colourised shell echo
• Colourised commands
• Recording editor activities for complex repetitions
• Capturing graphic images of X applications
• Tracking changes in configuration files

Data Storage Tips

• Disk partition configuration
• Accessing partitions using UUIDs
• Filesystem configuration
• Filesystem creation and integrity checks
• Filesystem optimization via mount options
• Filesystem optimization via superblocks
• Hard disk optimization
• Predicting hard disk failures with SMART
• Expanding usable storage space with LVM
• Expanding usable storage space by mounting additional partitions
• 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 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
• Starting programs from the GUI
• Customising launched programs
• Killing processes
• Scheduling one-time tasks
• Scheduling regular tasks
• 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 workflows
• 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
• System backup script examples
• Data backup copy scripts
• 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 into smaller chunks
• Clearing file contents
• Dummy files
• Erasing entire hard disks
• Erasing unused areas of hard disks
• Undeleting deleted but still open files
• Searching all hard links
• Invisible disk space consumption

Data Security Infrastructure

• GnuPG key management (signing and encrypting)
• The MD5 sum