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

The file system

• File system permissions
• Controlling permissions for new files: umask
• Group permissions for sets of users
• Timestamps
• Links
• Named pipes (FIFOs)
• Sockets
• Device files
• Special device files
• procfs and sysfs

Midnight Commander (MC)

• Customising MC
• Launching MC
• File manager features in MC
• Command-line tricks in MC
• The internal editor in MC
• The internal viewer in MC
• Auto-start features of MC
• MC's FTP virtual file system

The basic Unix-like work environment

• The login shell
• Customising bash
• Special key strokes
• The pager
• Setting a default text editor
• Exiting vim
• Recording shell activities
• Basic Unix commands

Simple shell commands

• Command execution and environment variables
• The "$LANG" variable
• The "$PATH" variable
• The "$HOME" variable
• Command line options
• Shell globbing
• Command return values
• Typical command sequences and shell redirection
• Command aliases

Unix-like text processing

• Unix text tools
• Regular expressions
• Replacement expressions
• Global substitution with regular expressions
• Extracting data from text file tables
• Script snippets for piping commands

Debian package management

Debian package management prerequisites

• Package configuration
• Essential precautions
• Managing ongoing upgrades
• Basics of the Debian archive
• Package dependencies
• The event flow of package management
• Initial response to package management issues

Basic package management operations

• Comparing apt-get/apt-cache with aptitude
• Basic package management operations via the command line
• Interactive use of aptitude
• Key bindings of aptitude
• Package views under 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
• Purging removed packages permanently
• Adjusting auto/manual install status
• Performing a system-wide upgrade

Advanced package management operations

• Advanced package management operations via command line
• Verifying installed package files
• Safeguards for package problems
• Searching package metadata

Debian package management internals

• Archive metadata
• Top-level "Release" file and authenticity
• Archive-level "Release" files
• Fetching metadata for packages
• 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

• Incompatibility with old user configuration
• Conflicting packages with overlapping files
• Fixing broken package scripts
• Rescue using the dpkg command
• Recovering package selection data

Tips for package management

• Selecting Debian packages
• Using packages from mixed archive sources
• Adjusting candidate versions
• Updates and Backports
• Automatic downloading and upgrading of packages
• Limiting APT download bandwidth
• Emergency downgrading
• Identifying the package uploader
• The equivs package
• Porting packages to stable systems
• APT proxy server configuration
• Small public package archives
• Recording and copying system configuration
• Converting or installing alien binary packages
• Extracting packages without dpkg
• Further reading on package management

System initialisation

• An 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
• The hostname
• The file system
• Network interface initialisation
• Network service initialisation
• System messages
• Kernel messages
• The udev system
• Kernel module initialisation

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 centralised system management
• "Why GNU su does not support the wheel group"
• Stricter password rules
• Other access controls
• sudo
• SELinux, Apparmor
• Restricting access to certain server services
• Authentication security
• Secure password transmission over the Internet
• Secure Shell
• Additional security measures for the Internet
• 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 optimisation

• Finding optimal MTU
• Setting MTU
• WAN TCP optimisation

Netfilter infrastructure

Network applications

The mail system

• Basics 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

The remote access server and utility (SSH)

• SSH basics
• Port forwarding for SMTP/POP3 tunneling
• Connecting without remote passwords
• Dealing with non-standard SSH clients
• Setting up ssh-agent
• Shutting down a remote system via SSH
• SSH troubleshooting

Other network application servers

Other network application clients

Diagnosis of 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
• Customising the X session (classic method)
• Customising the X session (new method)
• Connecting a remote X client via SSH
• Secure X terminal via 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 analyser
• Cleanly recording shell activities
• Customised display of text data
• Customised display of time and date
• Colourised shell echo
• Colourised commands
• Recording editor activities for complex repeats
• Recording graphic images of X applications
• Recording changes in configuration files

Data storage tips

• Disk partition configuration
• Accessing partitions using UUID
• File system configuration
• File system creation and integrity checks
• File system optimisation via mount options
• File system optimisation via superblock
• Hard disk optimisation
• Using SMART to predict hard disk failure
• Expanding usable storage space via LVM
• Expanding usable storage space by mounting another partition
• Expanding usable storage space using symlinks
• Expanding usable storage space using aufs

Data encryption tips

• Removable disk encryption with dm-crypt/LUKS
• Encrypted swap partition with dm-crypt
• Automatic file encryption with eCryptfs
• Automatic mounting of eCryptfs

Monitoring, controlling, and starting program activities

• Timing a process
• Setting 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
• Repeating a command looping over files
• Starting a program from GUI
• Customising startup programs
• Killing a process
• Scheduling one-off tasks
• Scheduling regular tasks
• The Alt-SysRq key

System maintenance tips

• Checking who is logged into the system
• Warning all users
• Hardware identification
• Hardware configuration
• System and hardware time
• Terminal configuration
• The 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 the kernel source: Debian standard method
• Compiling module source: Debian standard method
• Non-free hardware drivers

Virtualised systems

• Virtualisation tools
• Virtualisation workflow
• Mounting virtual disk image files
• Chroot systems
• Multiple desktop systems

Data management

Sharing, copying, and archiving

• Archive and compression tools
• Copy and synchronisation tools
• Idioms for archiving
• Idioms for copying
• Idioms for file selection
• Backup and recovery
• Backup utility suites
• An example script for system backup
• A copy script for data backup
• Removable storage devices
• Sharing data via 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
• Dummy files
• Erasing an entire hard disk
• Erasing unused areas of a hard disk
• Undeleting deleted but still open files
• Searching all hard links
• Hidden disk space consumption

Data security infrastructure

• Key management for GnuPG (signing and encrypting)
• The MD5 sum