Debian Administration Training Course

Debian Distribution

Understanding Debian

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

Console fundamentals

• The shell prompt
• The shell prompt in the X environment
• The root account and superuser shell prompt (su, sudo, executing programs as root under X)
• Graphical system administration tools
• Virtual consoles
• Exiting the command prompt
• Shutting down the system
• Restoring a stable console session
• Recommended additional packages for beginners
• Creating additional user accounts
• Configuring sudo

The Filesystem

• Filesystem permissions
• Controlling permissions for new files: umask
• Permissions for user groups
• Timestamps
• 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 utilities in MC
• MC’s internal editor
• MC’s internal viewer
• MC’s auto-start features
• MC’s FTP virtual filesystem

The basic Unix-like work environment

• The login shell
• Customising bash
• Special key combinations
• Using the pager
• Setting a default text editor
• Exiting vim
• Logging shell activities
• Essential 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 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
• Living with continuous upgrades
• Debian archive fundamentals
• Package dependencies
• The event flow in package management
• Initial responses to package management issues

Basic package management operations

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

Examples of aptitude operations

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

Advanced package management operations

• Advanced package management via the command line
• Verifying installed package files
• Mitigating package problems
• 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 in APT
• Package state in aptitude
• Local copies of fetched 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 using the dpkg command
• Restoring package selection data

Package management tips

• How to select Debian packages
• Packages from mixed archive sources
• Adjusting candidate versions
• Updates and Backports
• Automatic download and upgrade of packages
• Limiting download bandwidth for APT
• Emergency downgrading
• Identifying package uploaders
• The equivs package
• Porting a package to the stable system
• Configuring a proxy server for APT
• 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

The system initialization

• An overview of the bootstrapping process
• BIOS, boot loader, and the 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 information
• Creating strong passwords
• Generating 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 control mechanisms
• sudo
• SELinux and AppArmor
• Restricting access to specific server services
• Securing authentication
• Securing passwords over the Internet
• Secure Shell
• Additional Internet security measures
• Securing the root password

Network setup

The basic network infrastructure

• The domain name
• 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 the optimal MTU
• Setting the MTU
• WAN TCP optimization

Netfilter infrastructure

Network applications

The mail system

• Modern mail service fundamentals
• Mail configuration strategy for workstations

Mail transport agent (MTA) and Mail user agent (MUA)

• Overview of exim4
• Basic MUA usage - Mutt

Mail delivery agent (MDA) with filters

• maildrop configuration
• procmail configuration
• Redelivering mbox contents

POP3/IMAP4 server

The remote access server and utility (SSH)

• SSH fundamentals
• Port forwarding for SMTP/POP3 tunneling
• Connecting without remote passwords
• Handling non-standard SSH clients
• Setting up ssh-agent
• Shutting down a remote system 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 an X session with gdm
• Customizing the X session (classic method)
• Customizing the X session (modern method)
• Connecting a remote X client 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
• Colourized shell output
• Colourized commands
• Recording editor activities for complex repetitions
• Recording graphics from X applications
• Recording changes in configuration files

Data storage tips

• Disk partition configuration
• Accessing partitions using UUIDs
• Filesystem configuration
• Filesystem creation and integrity checks
• Optimizing filesystems via mount options
• Optimizing filesystems via the superblock
• Hard disk optimization
• Predicting hard disk failure using SMART
• Expanding usable storage space via LVM
• Expanding usable storage space by mounting additional partitions
• Expanding usable storage space using symbolic links
• Expanding usable storage space using aufs

Data encryption tips

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

Monitoring, controlling, and starting program activities

• Timing a process
• Scheduling priority
• The ps command
• The top command
• Listing files opened by a process
• Tracing program activities
• Identifying processes using files or sockets
• Repeating a command at constant intervals
• Looping a command over files
• Starting a program from the GUI
• Customizing which programs start
• Terminating a process
• Scheduling one-off tasks
• Scheduling recurring tasks
• The Alt-SysRq key

System maintenance tips

• Identifying users on the system
• Issuing warnings to all users
• Hardware identification
• Hardware configuration
• System and hardware time synchronization
• Terminal configuration
• 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
• 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 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
• Dummy files
• Wiping an entire hard disk
• Erasing unused areas of a hard disk
• Recovering deleted but still open files
• Finding all hard links
• Invisible disk space consumption

Data security infrastructure

• GnuPG key management (signing and encryption)
• The MD5 checksum