Debian Administration Training Course

Debian Distribution

What is Debian?

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

Console basics

• The shell prompt
• The shell prompt under X
• The root account and root shell prompt (su, sudo, running programs as root under X)
• GUI system administration tools
• Virtual consoles
• Exiting the command prompt
• Shutting down the system
• Restoring a stable console
• Recommended additional packages for beginners
• Creating an extra user account
• Configuring sudo

The filesystem

• Filesystem permissions
• Controlling permissions for newly created 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
• Using the file manager in MC
• Command-line techniques in MC
• The internal editor in MC
• The internal viewer in MC
• MC auto-start features
• MC FTP virtual filesystem

The basic Unix-like work environment

• The login shell
• Customizing bash
• Special key combinations
• The pager
• Setting a default text editor
• Quitting vim
• Logging shell activities
• Basic 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 tools
• 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
• Managing perpetual upgrades
• Basics of Debian archives
• Package dependencies
• The workflow of package management
• Initial steps for resolving package management issues

Basic package management operations

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

Examples of aptitude operations

• Listing packages using regex matching on names
• Browsing with regex matching
• Thoroughly purging removed packages
• Organizing auto/manual install status
• Performing a system-wide upgrade

Advanced package management operations

• Advanced package management via the command line
• Verifying installed package files
• Safeguards for package issues
• Searching package metadata

Internals of Debian package management

• 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

Recovering from a broken system

• Incompatibility with legacy user configurations
• Overlapping files between different packages
• Fixing broken package scripts
• Rescue procedures using the dpkg command
• Restoring package selection data

Tips for package management

• How to select Debian packages
• Packages from mixed archive sources
• Adjusting candidate versions
• Updates and Backports
• Automated download and upgrade of packages
• Limiting APT download bandwidth
• Emergency downgrading
• Identifying package uploaders
• The equivs package
• Porting a package to a stable system
• Proxy server configuration for APT
• Setting up a small public package archive
• Recording and copying system configuration
• 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
• Example runlevel management
• Default parameters for init scripts
• Hostname configuration
• 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
• 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 control mechanisms
• sudo
• SELinux, AppArmor
• Restricting access to specific server services
• Authentication security
• Secure password transmission over the Internet
• Secure Shell
• Additional security measures for Internet connectivity
• Securing the root password

Network setup

Basic network infrastructure

• Domain names
• Hostname resolution
• Network interface naming
• Network address ranges for LANs
• 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

• Modern mail service fundamentals
• 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 filtering

• 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 the 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
• Server/client relationships
• The X server
• Launching the X Window System
• Starting an X session with gdm
• Customizing the X session (traditional method)
• Customizing the X session (modern method)
• Connecting a remote X client via SSH
• Secure 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
• Neatly recording shell activities
• Customizing text data display
• Customizing time and date display
• Colorized shell echo
• Colorized commands
• Recording editor activities for complex repetitions
• Capturing graphics from X applications
• Tracking changes in configuration files

Data storage tips

• Disk partition configuration
• Accessing partitions using UUID
• Filesystem configuration
• Creating filesystems and checking integrity
• Optimizing filesystems via mount options
• Optimizing filesystems via superblock
• Optimizing hard disk performance
• Using SMART to predict hard disk failure
• Expanding usable storage space via LVM
• Expanding storage by mounting another partition
• Expanding storage using symbolic links
• Expanding storage using aufs

Data encryption tips

• Encrypting removable disks with dm-crypt/LUKS
• Encrypting the swap partition with dm-crypt
• Automatically encrypting files with eCryptfs
• Automatically mounting eCryptfs

Monitoring, controlling, and initiating 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 a constant interval
• Repeating a command across files
• Launching a program from the GUI
• Customizing programs to be started
• Terminating a process
• Scheduling a task once
• Scheduling tasks regularly
• The Alt-SysRq key

System maintenance tips

• Identifying active users on the system
• Issing warnings to all users
• Hardware identification
• Hardware configuration
• System and hardware time
• Terminal configuration
• Sound infrastructure
• Disabling the screen saver
• Disabling beep sounds
• Memory usage monitoring
• 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
• Multiple desktop systems

Data management

Sharing, copying, and archiving

• Archive and compression tools
• Copy and synchronization tools
• Common idioms for archiving
• Common idioms for copying
• Common idioms for file selection
• 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 the disk
• 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 areas of a hard disk
• Restoring deleted but still open files
• Searching all hard links
• Invisible disk space consumption

Data security infrastructure

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