Debian Administration Training Course

Debian Distribution

Introduction to Debian

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

Command-line fundamentals

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

The filesystem

• Filesystem permissions
• Controlling permissions for new files via 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
• Using the MC file manager
• Command-line shortcuts within MC
• MC’s internal editor
• MC’s internal viewer
• MC auto-start capabilities
• MC’s FTP virtual filesystem

The fundamental Unix-like workspace

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

Basic 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-style text processing

• Unix text utilities
• Regular expressions
• Replacement expressions
• 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
• Basic precautions
• Handling continuous upgrades
• Basics of Debian archives
• Package dependencies
• The workflow of package management
• Initial steps when facing package issues

Essential package management tasks

• Comparing apt-get/apt-cache with aptitude
• Basic package operations via the command line
• Using aptitude interactively
• aptitude key bindings
• Package views in aptitude
• Search options in aptitude
• The aptitude regex formula
• Dependency resolution in aptitude
• Logging package activities

aptitude operational examples

• Listing packages via regex matching on names
• Browsing with regex matching
• Permanently purging removed packages
• Organizing auto/manual install status
• Performing system-wide upgrades

Advanced package management tasks

• Advanced command-line package 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
• Retrieving package metadata
• 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 a corrupted system

• Addressing incompatibility with old user configs
• Handling packages with overlapping files
• Repairing broken package scripts
• Rescuing with the dpkg command
• Restoring package selection data

Package management tips

• Selecting appropriate Debian packages
• Using packages from mixed archive sources
• Adjusting candidate versions
• Updates and Backports
• Automatic package download and upgrade
• Limiting APT download bandwidth
• Emergency downgrading
• Identifying package uploaders
• The equivs package
• Porting packages to stable systems
• APT proxy server
• Maintaining small public package archives
• Recording and duplicating system configurations
• Converting or installing alien binary packages
• Extracting packages without dpkg
• Further reading on package management

System initialization

• Overview of the boot process
• BIOS, boot loader, and mini-Debian systems
• Understanding runlevels
• Configuring runlevels
• Example of runlevel management
• Default parameters for init scripts
• The hostname
• The filesystem
• Initializing network interfaces
• Initializing network services
• System messages
• Kernel messages
• The udev system
• Kernel module initialization

Authentication and Security

• Standard Unix authentication
• Managing account and password data
• Crafting strong passwords
• Creating 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
• Strict password policies
• Other access control methods
• sudo
• SELinux and Apparmor
• Restricting access to server services
• Authenticating securely
• Securing passwords over the internet
• Secure Shell
• Additional internet security measures
• Protecting the root password

Network setup

Fundamental 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

• Identifying optimal MTU
• Configuring MTU
• WAN TCP optimization

Netfilter infrastructure

Network applications

The mail system

• Modern mail service basics
• Mail configuration strategy for workstations

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

• Introduction to 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 basics
• Port forwarding for SMTP/POP3 tunneling
• Passwordless remote connections
• Interacting with non-standard SSH clients
• Setting up ssh-agent
• Shutting down remote systems via SSH
• Debugging 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 (traditional 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 logging and presentation

• The log daemon
• Log analyzers
• Cleanly recording shell sessions
• Customizing text data display
• Customizing time and date display
• Colorized shell echo
• Colorized commands
• Logging editor actions for complex repetitions
• Capturing graphical output of X applications
• Tracking 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
• Optimizing hard disks
• Using SMART to predict disk failure
• Expanding storage space via LVM
• Expanding storage by mounting additional partitions
• Expanding storage using symlinks
• Expanding storage using aufs

Data encryption tips

• Encrypting removable disks with dm-crypt/LUKS
• Encrypting swap partitions with dm-crypt
• Automatic file encryption with eCryptfs
• Automatic mounting of eCryptfs

Monitoring, controlling, and initiating 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
• Repeating commands at constant intervals
• Repeating commands across file loops
• Launching programs from the GUI
• Customizing which programs start
• Terminating a process
• Scheduling one-time tasks
• Scheduling regular tasks
• The Alt-SysRq key

System maintenance tips

• Identifying active users on the system
• Warning all users
• Hardware identification
• Hardware configuration
• System and hardware time
• Terminal configuration
• The 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 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
• Managing 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
• Recovering data files and forensic analysis
• Splitting large files into smaller ones
• Clearing file contents
• Dummy files
• Erasing an entire hard disk
• Erasing unused hard disk areas
• Recovering deleted but still open files
• Finding all hard links
• Hidden disk space consumption

Data security infrastructure

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