Linux Administration Handbook

About

Features

• Sophisticated centralized management techniques—Presents specific techniques for centrally managing multiple RedHat, Debian, and/or SuSe Linux servers.

  • Teaches students to administer multiple Linux systems far more efficiently.

• Enterprise-class performance measurement and optimization—Teaches students to quantify the potential performance of Linux systems, identify bottlenecks, and ameliorate them.

  • Gives students key skills for maximizing the value of Linux systems in any real-world environment and teaches them to protect the data and applications they will be responsible for.

• Detailed RedHat, Debian, and SuSe coverage—Covers all three of the Linux distributions used most often in large-scale Linux deployments.

  • Offers well-targeted preparation for the Linux environments students are most likely to encounter.

• Broad, expert-class application coverage—Includes detailed coverage of configuring and administering sendmail, file and print services, web hosting, and other key applications.

  • Covers the Linux capabilities that are in greatest demand in real-world production environments.

• Extensive networking coverage—Presents practical guidance for working with TCP/IP networking, routing, network hardware, the Network File System, and other key network-related Linux features.

  • Helps students become effective in administering complex, networked environments.

• Step-by-step security coverage—Shows students how to secure Linux systems against intrusion and other current threats.

  • Teaches students how to protect servers, data, and applications against a wide range of external threats.

• Practical troubleshooting techniques—Includes coverage of reading, interpreting, and acting upon information available through syslog and log files.

  • Enables students to independently resolve a wide range of Linux system administration problems.



Description

• Copyright 2002
• Edition: 1st

• Book
• ISBN-10: 0-13-008466-2
• ISBN-13: 978-0-13-008466-8

As the deployment of Linux systems in production environments has accelerated, Linux administrators have longed for a book that addresses the challenges of this complex and exciting frontier. Linux Administration Handbook was written with this audience in mind. This book serves both as a valuable tutorial for the novice administrator and as a trustworthy reference for the seasoned professional. Using the practical approach of their highly regarded UNIX System Administration Handbook, the authors describe every aspect of Linux system administration and cover the following major Linux distributions: Red Hat Linux, SuSE Linux, Debian GNU/Linux.

Replete with war stories and hard-won insights, this book examines how Linux systems behave in real-world ecosystems, not how they might behave in ideal environments. Difficult tasks are described in all their complexity, including DNS configuration, networking, sendmail configuration, security management, kernel building, performance analysis, and routing. The book's many true-life examples will help administrators implement solutions that continue to work effectively as their operations grow.

"As this book shows, Linux systems are just as functional, secure, and reliable as their proprietary counterparts. Thanks to the ongoing efforts of its thousands of developers, Linux is more ready than ever for deployment at the frontlines of the real world. The authors of this book know that terrain well, and I am happy to leave you in their most capable hands."

—Linus Torvalds

"I'm absolutely amazed to see a computing book that focuses on concepts and how to implement them instead of explaining man pages for dummies. I also find the historical remarks very interesting. Your book is the very best of its kind I have ever read."

—Hanspeter Schmid, Bernafon, Switzerland

"I just wanted to tell you guys that I have learned more about system administration from your book than from $10,000 worth of training classes. This book has been an invaluable part of my day-to-day life as a system and network administrator."

—Chris Bourne, Xapnet, Emeryville, CA

"The seminal work in the field. If you can have only one system administration book, this should be it."

—Brad Knowles, Brussels, Belgium



Extras

Related Article

Rsyncing to New Heights in Linux Lore



Sample Content

Online Sample Chapter

Linux Drivers and the Kernel

Table of Contents

Foreword.


Preface.


Acknowledgments.

BASIC ADMINISTRATION.

1.Where to Start.

Suggested background. Linux's relationship to UNIX. Linux and UNIX history. Linux distributions. Notation and typographical conventions. Where to go for information. How to find and install software. Essential tasks of the system administrator. System administration under duress. Recommended reading. Exercises.

2.Booting and Shutting Down.

Bootstrapping. Booting PCs. Boot loaders: LILO and GRUB. Booting single-user mode. Startup Scripts. Rebooting and shutting down. Exercises.

3. Rootly Powers.

Ownership of files and processes. The superuser. Choosing a root password. Becoming root. Other pseudo-users. Exercises.

4. Controlling Processes.

Components of a process. The life cycle of a process. Signals. kill and killall: send signals. Process states. nice and renice: influence scheduling priority. ps: monitor processes. top: monitor processes even better. Runaway processes. Exercises.

5. The Filesystem.

Pathnames. Mounting and unmounting filesystems. The organization of the file tree. File types. File attributes. Exercises.

6. Adding New Users.

The /etc/passwd file. The /etc/shadow file. The /etc/group file. Adding users. Removing users. Disabling logins. Account management utilities. Exercises.

7. Serial Devices.

Serial standards. Alternative connectors. Hard and soft carrier. Hardware flow control. Cable length. Serial device files. setserial: tell the driver about serial port parameters. Software configuration for serial devices. Configuration of hardwired terminals. Special characters and the terminal driver. stty: set terminal options. tset: set options automatically. How to unwedge a terminal. Modems. Debugging a serial line. Other common I/O ports. Exercises.

8. Adding A Disk.

Disk interfaces. Disk geometry. An overview of the disk installation procedure. The ext2 and ext3 filesystems. fsck: check and repair filesystems Adding a disk to Linux: a step-by-step guide. Exercises.

9. Periodic Processes.

cron: schedule commands. The format of crontab files. Crontab management. Some common uses for cron. Exercises.

10. Backups.

Motherhood and apple pie. Backup devices and media. Setting up an incremental backup regime with dump. Restoring from dumps with restore. Dumping and restoring for upgrades. Using other archiving programs. Using multiple files on a single tape. Amanda. Commercial backup products. Recommended reading. Exercises.

11. Syslog and Log Files.

Logging policies. Linux log files. logrotate: manage log files. Syslog: the system event logger. Condensing log files to useful information. Exercises

12. Drivers and The Kernel.

Kernel adaptation. Why configure the kernel? Configuration methods. Tuning a Linux kernel. Adding device drivers. Adding a Linux device driver. Device files. Loadable kernel modules. Building a Linux kernel. Don't fix it if it ain't broken. Recommended reading. Exercises.

NETWORKING.

13. TCP/IP Networking.

TCP/IP and the Internet. Networking road map. Packets and encapsulation. IP addresses: the gory details. Routing. ARP: The address resolution protocol. Adding a machine to a network. Distribution-specific network configuration. DHCP: the Dynamic Host Configuration Protocol. Linux dynamic reconfiguration and tuning. Security issues. Linux NAT (IP masquerading) PPP: the Point-to-Point Protocol. Linux networking quirks. Recommended reading Exercises.

14. Routing.

Packet forwarding: a closer look. Routing daemons and routing protocols. Protocols on parade. routed: RIP yourself a new hole. gated: a better routing daemon. Routing strategy selection criteria. Cisco routers. Recommended reading. Exercises.

15. Network Hardware

LAN, WAN, or MAN? Ethernet: the common LAN. Wireless: the nomad's LAN. FDDI: the disappointing and expensive LAN. ATM: the promised (but sorely defeated) LAN. Frame relay: the sacrificial WAN. ISDN: the indigenous WAN. DSL and cable modems: the people's WAN. Where is the network going? Network testing and debugging. Building wiring. Network design issues. Management issues. Recommended vendors. Recommended reading. Exercises.

16. The Domain Name System.

DNS for the impatient: adding a new machine. The history of DNS. Who needs DNS? What's new in DNS. The DNS namespace. The BIND software. How DNS works. BIND client issues. BIND server configuration. BIND configuration examples. The DNS database. Updating zone files. Security issues. Testing and debugging. Loose ends. Distribution specifics. Recommended reading. Exercises.

17. The Network File System.

General information about NFS. Server-side NFS. Client-side NFS. nfsstat: dump NFS statistics. Dedicated NFS file servers. Automatic mounting. Automount. amd: a more sophisticated automounter. Recommended reading. Exercises.

18. Sharing System Files.

What to share. Copying files around. NIS: the Network Information Service. NIS+: son of NIS. LDAP: the Lightweight Directory Access Protocol. Exercises.

19. Electronic Mail.

Mail systems. The anatomy of a mail message. Mail philosophy. Mail aliases. sendmail: ringmaster of the electronic mail circus. sendmail configuration. Basic sendmail configuration primitives. Fancier sendmail configuration primitives. Configuration file examples. Spam-related features in sendmail. Security and sendmail. Sendmail performance. sendmail statistics, testing, and debugging. The Exim Mail System. Recommended reading. Exercises

20. Network Management and Debugging.

Troubleshooting a network. ping: check to see if a host is alive. traceroute: trace IP packets. netstat: get tons o' network statistics. Packet sniffers. Network management protocols. SNMP: the Simple Network Management Protocol. The NET-SMNP agent. Network management applications. Recommended reading. Exercises.

21. Security.

Is Linux secure? Linux security, the CliffsNotes version. How security is compromised. Security problems in the /etc/passwd and /etc/shadow files. Setuid programs. Important file permissions. Miscellaneous security issues. Security power tools. Cryptographic security tools. Firewalls. Linux firewall features: IP tables. Virtual private networks (VPNs). Sources of security information. Hardened Linux distributions. What to do when your site has been attacked. Recommended reading. Exercises.

22. Web Hosting and Internet Servers.

Web hosting. Web hosting basics. HTTP server installation. Virtual interfaces. Caching and proxy servers. Anonymous FTP server setup. Exercises.

BUNCH O' STUFF.

23. Software Installation and Localization.

Basic Linux installation. Automating installation. Localization. Keeping your systems up to date with rsync or rdist. Package management. apt-get: automate downloading and installation. Recommended reading. Exercises.

24. Printing.

Mini-glossary of printing terms. Linux printing. Types of printers. LPD: the good ol' printing system. LPRng. Adding a printer. Debugging printing problems. Common printing software. Printer philosophy. Exercises.

25. Maintenance and Environment.

Maintenance basics. Maintenance contracts. Board-handling lore. Monitors. Memory modules. Preventive maintenance. Environment. Power. Racks. Tools. Exercises.

26. Performance Analysis.

What you can do to improve performance. Factors that affect performance. System performance checkup. Help! My system just got really slow! Recommended reading. Exercises.

27. Cooperating with Windows.

File and print sharing. Secure terminal emulation with SSH. X Windows emulators. PC mail clients. PC backups. Dual booting. Running Windows applications under Linux. PC hardware tips. Recommended reading. Exercises.

28. Daemons.

init: the primordial process. cron and atd: schedule commands. inetd and xinetd: manage daemons. Kernel daemons. File service daemons. Administrative database daemons. Internet daemons. Time synchronization daemons. Booting and configuration daemons. Exercises.

29. Policy and Politics.

Linux culture. Policy and procedure. Legal issues. Scope of service. Trouble-reporting systems. Managing management. Hiring, firing, and training. War stories and ethics. Local documentation. Procurement. Decommissioning hardware. Organizations, conferences, and other resources. Standards. Sample documents. Recommended reading. Exercises.

Colophon.
Index.

Preface

Preface

Linux is a relatively new operating system in the world of computing. Born in the early 1990s, it has enjoyed tremendous publicity and support from the open source community. In many ways, Linux has come to represent the antimatter of an otherwise Microsoft-centric universe.

Despite Linux's many achievements, it has yet to gain full acceptance in the world of "production computing." Once synonymous with big-iron mainframes, this environment is a world in which a few minutes of downtime can cost millions of dollars, dozens of jobs, or in extreme cases, lives.

We think it's about time that Linux was accepted as a fully ordained member of this community. However, such acceptance can only develop with the help of a cavalry of professional Linux system administrators.

We set out to write a book that would be the professional Linux system administrator's best friend. Where appropriate, we've adapted the proven concepts and materials from our popular book, UNIX System Administration Handbook. We've added a truckload of Linux-specific material and updated the rest, but much of the coverage remains similar. We hope you agree that the result is a high-quality guide to Linux administration that benefits from its experience in a past life.

There are other books on Linux system administration, but none that provide the breadth and depth of material necessary to effectively use Linux in real-world business environments. Here are the features that distinguish our book:

• We take a practical approach. Our purpose is not to restate the contents of your manuals but rather to summarize our collective experience in system administration. This book contains numerous war stories and a wealth of pragmatic advice.
• This is not a book about how to run Linux at home, in your garage, or on your PDA. We describe the use of Linux in production environments such as businesses, government offices, and universities.
• We cover Linux networking in detail. It is the most difficult aspect of system administration and the area in which we think we can be of most help.
• We do not oversimplify the material. Our examples reflect true-life situations with all their warts and unsightly complications. In most cases, the examples have been taken directly from production systems.
• We cover three major Linux distributions.

Our example distributions

Like so many operating systems, Linux has grown and branched in several different directions. Although development of the kernel has remained surprisingly centralized, packaging and distribution of complete Linux operating systems is overseen by a variety of groups, each with its own agenda.

We cover three Linux distributions in detail:

• Red Hat 7.2
• SuSE 7.3
• Debian 3.0

We chose these distributions because they are among the most popular and because they are representative of the Linux community as a whole. However, much of the material in this book applies to other mainstream distributions as well.

We provide detailed information about each of these example distributions for every topic that we discuss. Comments specific to a particular operating system are marked with the distribution's logo.

The organization of this book

This book is divided into three large chunks: Basic Administration, Networking, and Bunch o' Stuff.

Basic Administration provides a broad overview of Linux from a system administrator's perspective. The chapters in this section cover most of the facts and techniques needed to run a stand-alone Linux system.

The Networking section describes the protocols used on Linux systems and the techniques used to set up, extend, and maintain networks. High-level network software is also covered here. Among the featured topics are the Domain Name System, the Network File System, routing, sendmail, and network management.

Bunch o' Stuff includes a variety of supplemental information. Some chapters discuss optional software packages such as the Linux printing system. Others give advice on topics ranging from hardware maintenance to the politics of running a Linux installation.

Each chapter is followed by set of practice exercises. Items are marked with our estimate of the effort required to complete them, where "effort" is an indicator of both the difficulty of the task and the time required.

There are four levels:

no stars	Easy, should be straightforward
*	Harder or longer, may require lab work
**	Hardest or longest, requires lab work and digging
*****	Semester-long projects (only in a few chapters)

Some of the exercises require root or sudo access to the system; others require the permission of the local sysadmin group. Both requirements are mentioned in the text of the exercise.

Our contributors

We're delighted that Adam Boggs, Matt Crosby, and Ned McClain were able to participate as contributing authors. Their deep knowledge of a variety of areas has greatly enriched the content of this book. We owe them special thanks for making this book possible. Adam did a wonderful job delivering more than he promised, Matt was a master of pulling a high-quality rabbit out of a hat, and Ned was our much needed (and always enthusiastic) jack-of-all-trades.

Contact information

Please send suggestions, comments, typos, and bug reports to sa-book@admin.com. We answer most mail, but please be patient; it is sometimes a few days before one of us is able to respond. To get a copy of our current bug list and other late-breaking information, visit our web site, www.admin.com

We hope you enjoy this book, and we wish you the best of luck with your adventures in system administration!

Evi Nemeth
Garth Snyder
Trent R. Hein

April 2002



Updates

Submit Errata

