Debian Administration Training Course

Debian Distribution

What is Debian?

• Choosing a Debian version
• Debian support and resources
• The Debian community

Console basics

• The shell prompt
• The shell prompt within the X environment
• Root account and root shell prompt (su, sudo, executing programs as root under X)
• GUI system administration tools
• Virtual consoles
• Exiting the command prompt
• System shutdown procedures
• Recovering a stable console
• Recommended packages for beginners
• Creating an additional user account
• Configuring sudo

The filesystem

• Filesystem permissions
• Controlling permissions for new files: umask
• Group permissions (group)
• Timestamps
• Symbolic links
• Named pipes (FIFOs)
• Sockets
• Device files
• Special device files
• procfs and sysfs

Midnight Commander (MC)

• Customizing MC
• Launching MC
• The file manager within MC
• Command-line techniques in MC
• The internal editor in MC
• The internal viewer in MC
• Auto-start capabilities in MC
• MC's FTP virtual filesystem

The basic Unix-like work environment

• The login shell
• Customizing bash
• Special key combinations
• Using the pager
• Setting a default text editor
• Exiting vim
• Logging shell activities
• Fundamental 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
• 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 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 fundamentals
• Package dependencies
• The workflow of package management
• Initial response to package management issues

Basic package management operations

• apt-get/apt-cache vs. aptitude
• Basic package operations via the command line
• Interactive usage of aptitude
• aptitude key bindings
• Package views in aptitude
• Search options in aptitude
• The aptitude regex formula
• Dependency resolution in aptitude
• Package activity logs

Examples of aptitude operations

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

Advanced package management operations

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

Debian package management internals

• 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 downloaded packages
• Debian package file naming conventions
• The dpkg command
• The update-alternatives command
• The dpkg-statoverride command
• The dpkg-divert command

Recovery from a broken system

• Incompatibility with legacy user configurations
• Packages with overlapping files
• Repairing broken package scripts
• Rescue operations using the dpkg command
• Restoring package selection data

Tips for package management

• Selecting Debian packages
• 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
• 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 bootstrapping process
• BIOS, boot loader, and mini-Debian system
• The concept of runlevels
• Configuring runlevels
• Runlevel management examples
• Default parameters for init scripts
• The hostname
• 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 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"
• Stricter password policies
• Other access controls
• sudo
• SELinux, Apparmor
• Restricting access to server services
• Authentication security
• Securing passwords over the Internet
• Secure Shell
• Additional security measures for Internet-facing systems
• Securing the root password

Network setup

The basic network infrastructure

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

• Determining optimal MTU
• Configuring MTU
• WAN TCP optimization

Netfilter infrastructure

Network applications

The mail system

• Fundamentals 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 server

Remote access server and utility (SSH)

• SSH fundamentals
• Port forwarding for SMTP/POP3 tunneling
• Connecting without remote passwords
• Interacting with non-standard 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
• Server/client relationships
• The X server
• Launching the X Window System
• Starting X sessions with gdm
• Customizing X sessions (traditional method)
• Customizing 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
• Recording shell activities effectively
• Custom text data display
• Custom time and date display
• Colorized shell output
• Colorized commands
• Recording editor actions for complex repeats
• Capturing graphical images of X applications
• Tracking changes in configuration files

Data storage tips

• Disk partition configuration
• Accessing partitions via UUID
• Filesystem configuration
• Filesystem creation and integrity checks
• Filesystem optimization via mount options
• Filesystem optimization via superblock
• Hard disk optimization
• Predicting hard disk failure using SMART
• Expanding storage space via LVM
• Expanding storage space by mounting additional partitions
• Expanding storage space using symlinks
• Expanding 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 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 fixed intervals
• Looping command execution over files
• Launching programs from the GUI
• Customizing startup programs
• Terminating processes
• Scheduling one-time tasks
• Scheduling recurring tasks
• The Alt-SysRq key

System maintenance tips

• Identifying users on the system
• Broadcasting warnings to users
• 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 image files
• Chroot systems
• Multiple desktop systems

Data management

Sharing, copying, and archiving

• Archiving and compression tools
• Copying 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 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 ones
• Clearing file contents
• Placeholder files
• Erasing entire hard disks
• Erasing unused areas of a hard disk
• Undeleting deleted but still open files
• Locating all hard links
• Invisible disk space consumption

Data security infrastructure

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