Debian Administration Training Course

Debian Distribution

What is Debian?

• Selecting the appropriate Debian version
• Accessing Debian support and resources
• Engaging with the Debian community

Console Fundamentals

• Understanding the shell prompt
• Navigating the shell prompt within the X environment
• Utilizing the root account and root shell prompt (su, sudo, executing programs as root under X)
• GUI-based system administration tools
• Managing virtual consoles
• Exiting the command prompt
• Properly shutting down the system
• Restoring a functional console state
• Recommended packages for beginners
• Setting up an additional user account
• Configuring sudo

The Filesystem

• Filesystem permissions
• Controlling permissions for newly created files via umask
• Managing permissions for user groups (group)
• Understanding timestamps
• Working with links
• Named pipes (FIFOs)
• Socket types
• Device files
• Special device files
• Using procfs and sysfs

Midnight Commander (MC)

• Customizing MC
• Launching MC
• Using the MC file manager
• Advanced command-line tricks in MC
• Utilizing the internal editor in MC
• Utilizing the internal viewer in MC
• Auto-start configurations for MC
• Accessing MC's FTP virtual filesystem

The Basic Unix-like Work Environment

• Understanding the login shell
• Customizing bash
• Using special keystrokes
• Utilizing the pager
• Setting a default text editor
• Navigating out of vim
• Recording shell activities
• Mastering basic Unix commands

Basic Shell Commands

• Command execution and environment variables
• Understanding the "$LANG" variable
• Understanding the "$PATH" variable
• Understanding the "$HOME" variable
• Using command line options
• Shell globbing
• Interpreting command return values
• Common command sequences and shell redirection
• Creating command aliases

Unix-like Text Processing

• Overview of Unix text tools
• Working with regular expressions
• Using replacement expressions
• Performing global substitution with regular expressions
• Extracting data from text file tables
• Creating script snippets for piping commands

Debian Package Management

Prerequisites for Debian Package Management

• Package configuration
• Essential precautions
• Managing ongoing upgrades
• Basics of the Debian archive
• Understanding package dependencies
• The lifecycle of package management
• Initial responses to package management issues

Basic Package Management Operations

• Comparing apt-get/apt-cache vs. aptitude
• Performing basic package management operations via the command line
• Interactive use of aptitude
• Key bindings in aptitude
• Navigating package views under aptitude
• Search method options with aptitude
• Using the aptitude regex formula
• Dependency resolution within aptitude
• Reviewing package activity logs

Examples of aptitude Operations

• Listing packages with regex matching on package names
• Browsing using regex matching
• Permanently purging removed packages
• Refining auto/manual install statuses
• Performing a system-wide upgrade

Advanced Package Management Operations

• Executing advanced package management operations via the command line
• Verifying installed package files
• Precautions against package issues
• Searching package metadata

Debian Package Management Internals

• Archive metadata
• The top-level "Release" file and authenticity verification
• Archive-level "Release" files
• Fetching metadata for packages
• Package states for APT
• Package states for aptitude
• Local copies of fetched packages
• Debian package file naming conventions
• Using the dpkg command
• Using the update-alternatives command
• Using the dpkg-statoverride command
• Using the dpkg-divert command

Recovering from a Broken System

• Addressing incompatibility with old user configurations
• Handling different packages with overlapping files
• Repairing broken package scripts
• Rescue operations using the dpkg command
• Recovering package selection data

Tips for Package Management

• Selecting Debian packages
• Managing 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
• Using the equivs package
• Porting packages to a stable system
• Configuring an APT proxy server
• Managing small public package archives
• Recording and copying system configurations
• Converting or installing alien binary packages
• Extracting packages without dpkg
• Additional resources for package management

System Initialization

• Overview of the boot strap process
• BIOS, boot loaders, and the mini-Debian system
• Understanding runlevels
• Configuring runlevels
• Runlevel management examples
• Default parameters for each init script
• Managing the hostname
• Filesystem handling
• 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 information
• Best practices for strong passwords
• Creating encrypted passwords
• Understanding 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 and Apparmor
• Restricting access to specific server services
• Ensuring authentication security
• Secure password transmission over the Internet
• Securing Shell (SSH)
• Additional security measures for Internet exposure
• Securing the root password

Network Setup

Basic 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

• Using Iproute2 commands
• Safely performing low-level network operations

Network Optimization

• Identifying optimal MTU
• Setting MTU
• WAN TCP optimization

Netfilter Infrastructure

Network Applications

The Mail System

• Basics 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

• Configuring maildrop
• Configuring procmail
• Redelivering mbox contents

POP3/IMAP4 Server

Remote Access Server and Utility (SSH)

• SSH basics
• Port forwarding for SMTP/POP3 tunneling
• Connecting without remote passwords
• Handling 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
• Understanding 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 (new 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 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
• Creating and checking filesystem integrity
• Optimizing filesystems via mount options
• Optimizing filesystems via superblock
• Optimizing hard disks
• Using SMART to predict hard disk failure
• Expanding usable storage via LVM
• Expanding usable storage by mounting another partition
• Expanding usable storage using symlinks
• Expanding usable storage using aufs

Data Encryption Tips

• Encrypting removable disks with dm-crypt/LUKS
• Encrypting swap partitions with dm-crypt
• Automatically encrypting files with eCryptfs
• Automounting 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 a constant interval
• Repeating a command looping over files
• Starting a program from the GUI
• Customizing program startup
• Killing a process
• Scheduling one-time tasks
• Scheduling recurring tasks
• Using the Alt-SysRq key

System Maintenance Tips

• Identifying users on the system
• Broadcasting warnings to all users
• Hardware identification
• Hardware configuration
• System and hardware time synchronization
• 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 the 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
• Idioms for archiving
• Idioms for copying
• Idioms for file selection
• Backup and recovery
• Backup utility suites
• Example script for system backup
• Script for data backup
• Removable storage devices
• Sharing data via the network
• Archive media

Binary Data

• Viewing and editing binary data
• Manipulating files without mounting the disk
• Data redundancy
• Data file recovery and forensic analysis
• Splitting large files into smaller ones
• 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 hardlinks
• Identifying invisible disk space consumption

Data Security Infrastructure

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