Debian Administration Training Course

Debian Distribution

What is Debian?

• Selecting the appropriate Debian version
• Debian support and assistance resources
• The Debian community

Console fundamentals

• Understanding the shell prompt
• The shell prompt within the X environment
• The root account and root shell prompt (utilizing su, sudo, and running programs as root under X)
• GUI-based system administration tools
• Virtual consoles
• Exiting the command prompt
• Shutting down the system
• Restoring a functional console
• Recommended packages for beginners
• Setting up an additional user account
• Configuring sudo

The filesystem

• Filesystem permissions
• Managing permissions for new files: umask
• Permissions for user groups (group)
• Timestamps
• Hard and symbolic links
• Named pipes (FIFOs)
• Sockets
• Device files
• Special device files
• procfs and sysfs

Midnight Commander (MC)

• Customizing MC
• Launching MC
• File management within MC
• Command-line techniques in MC
• MC's internal editor
• MC's internal viewer
• Auto-start features of MC
• MC's FTP virtual filesystem

The basic Unix-like work environment

• The login shell
• Customizing bash
• Essential keystrokes
• Using the pager
• Setting a default text editor
• Exiting vim
• Recording shell activities
• Fundamental 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-like text processing

• Unix text utilities
• 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
• Essential precautions
• Navigating continuous upgrades
• Debian archive fundamentals
• Package dependencies
• The package management event flow
• 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 in aptitude
• Search method options with aptitude
• The aptitude regex formula
• Dependency resolution in aptitude
• Package activity logs

Examples of aptitude operations

• Listing packages with regex matching on package names
• Browsing with regex matching
• Permanently purging removed packages
• Managing auto/manual installation status
• Performing a system-wide upgrade

Advanced package management operations

• Advanced package management operations via command line
• Verifying installed package files
• Precautions for package issues
• Searching package metadata

Debian package management internals

• Archive metadata
• The 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 conventions
• The dpkg command
• The update-alternative command
• The dpkg-statoverride command
• The dpkg-divert command

Recovery from a broken system

• Resolving incompatibilities with old user configurations
• Handling packages with overlapping files
• Fixing broken package scripts
• Rescue operations using the dpkg command
• Recovering package selection data

Tips for package management

• How to select Debian packages
• Managing 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
• Using the equivs package
• Porting packages to a stable system
• Configuring an APT proxy server
• Utilizing small public package archives
• Recording and copying system configurations
• Converting or installing alien binary packages
• Extracting packages without dpkg
• Further reading on package management

The system initialization

• Overview of the bootstrap process
• BIOS, boot loader, and mini-Debian system
• Understanding runlevels
• Configuring runlevels
• Runlevel management examples
• Default parameters for each init script
• Configuring the hostname
• Filesystem initialization
• 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 accessed by PAM and NSS
• Modern centralized system management
• Why GNU su does not support the wheel group
• Implementing stricter password rules
• Other access control methods
• Using sudo
• SELinux, Apparmor
• Restricting access to specific server services
• Authentication security
• Secure password transmission over the Internet
• Secure Shell (SSH)
• Additional security measures for Internet services
• 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

• Finding optimal MTU
• Setting MTU
• WAN TCP optimization

Netfilter infrastructure

Network applications

The mail system

• Fundamentals of modern mail services
• Mail configuration strategies 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
• Redistributing mbox contents

POP3/IMAP4 server

The remote access server and utility (SSH)

• SSH basics
• Port forwarding for SMTP/POP3 tunneling
• Connecting without remote passwords
• Managing incompatible SSH clients
• Setting up ssh-agent
• Shutting down a remote system 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 relationship
• The X server
• Starting the X Window System
• Starting an X session with gdm
• Customizing the X session (classic method)
• Customizing the X session (new method)
• Connecting a remote X client via SSH
• Securing an X terminal 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
• Customizing text data display
• Customizing time and date display
• Colorized shell echo
• Colorized commands
• Recording editor activities for complex repetitions
• Recording the graphic image of an X application
• Recording changes in configuration files

Data storage tips

• Disk partition configuration
• Accessing partitions using UUID
• Filesystem configuration
• Filesystem creation and integrity checks
• Optimizing filesystems via mount options
• Optimizing filesystems via superblock
• Hard disk optimization
• Using SMART to predict hard disk failures
• Expanding usable storage space via 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
• Creating encrypted swap partitions with dm-crypt
• Automatically encrypting files with eCryptfs
• Automatically mounting eCryptfs

Monitoring, controlling, and starting program activities

• Timing a process
• Setting scheduling priority
• Using the ps command
• Using the top command
• Listing files opened by a process
• Tracing program activities
• Identifying processes using files or sockets
• Repeating a command at constant intervals
• Repeating a command looping over files
• Starting a program from the GUI
• Customizing programs to start automatically
• Killing a process
• Scheduling one-time tasks
• Scheduling recurring tasks
• Using the Alt-SysRq key

System maintenance tips

• Identifying logged-in users
• Notifying all users
• Hardware identification
• Hardware configuration
• System and hardware time
• Terminal configuration
• Sound infrastructure
• Disabling the screen saver
• Disabling beep sounds
• Monitoring 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 workflow
• 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
• Archive idioms
• Copy idioms
• File selection idioms
• Backup and recovery
• Backup utility suites
• Example script for system backup
• Cop script for data backup
• 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 parts
• Clearing file contents
• Creating dummy files
• Erasing an entire hard disk
• Erasing unused areas of a hard disk
• Undeleting deleted but still open files
• Searching for all hard links
• Identifying invisible disk space consumption

Data security infrastructure

• Key management for GnuPG (signing and encrypting)
• MD5 sums