UNIX Unleashed

Robin Anderson began her involvement with computers innocently enough with an Amiga, WordPerfect, and Infocom games. In late 1993, she turned her hand to student consulting at the University of MD, Baltimore County (UMBC), working with PCs, Macs, VAXen, and, finally, UNIX machines. After graduating with honors in Computer Science and History, Robin remained at UMBC and is now a UNIX SysAdmin Specialist in OIT (UMBC's Office of Information Technology). She also managed OIT's Operations Support Staff and is a member of the Security Work Group. Robin developed and taught an undergraduate UNIX SysAdmin course for UMBC's CS/EE department in 2000. She has earned two security certifications from the SANS Institute: the GCUX (UNIX Administrator, with honors) and the GCIH (Incident Handling). She works with SANS to develop online exam materials and presentations, and she recently taught SANS LevelOne security courses for UMBC's Department of Professional Education and Training. Andy Johnston was born in May of 1958. Most of the rest has been improvisation. After teaching high school math, he became a programmer. He worked for the State of Maryland making population projections and lots of maps, and later for Computer Sciences Corporation, where he worked on spacecraft-tracking software and environmental modeling. One day, the UNIX system in which his virtual fish swam suffered a drive crash, and he (quickly) became a UNIX systems administrator. Andy provided system support for several projects, including the International Ultraviolet Explorer. In 1999, he took his current position at the University of Maryland, Baltimore County (UMBC)Office of Information Technology as a manager of UNIX support staff and IT security. Andy holds a Bachelor's degree in Biology from Princeton University and a Master's degree in Mathematics from UMBC. He has been involved at various times in the Baltimore and Washington, D.C. SAGE groups and has spoken at SANS conferences.

Introduction.
I. BASIC OPERATION.

1. Startup and Shutdown.


Introduction. Outlining the Five-Step Boot Process. Step 1: Firmware—Hardware Self-Recognition. Step 2: Bootloader—Loading the OS. Step 3: Kernel—Initialization and Control Transfer. Step 4: Init and Initialization Scripts. Step 5: Over to the Admin—Miscellaneous Wrap-Up. Shutting Down and Generally Changing init Levels. The Red Hat Boot Sequence as Displayed by dmesg. The Solaris Boot Sequence as Displayed by mesg. Best Practices. Online References. Endnotes.

2. Managing Disk Hardware.


Introduction. Physical Devices. OS-Independent Hardware Communication Standards. Know Your System. Adding/Removing Disks (and Other Devices). Best Practices. Online References. Endnotes.

3. Filesystem Administration.


Introduction. Dividing Disk Space Wisely. More About Filesystems. Administering Local Filesystems. Administering Local Filesystems. Removable Storage Media. Best Practices. Online References. Endnotes.

4. User Administration.


Definitions: Identity, Entity, Capability. Storing Basic User Information Locally. Sharing User (and Other) Information over the Network. Creating Accounts. Removing Accounts. Best Practices. Online References. Endnotes.

5. Getting on the Network.


Introduction. TCP/IP. Best Practices. Online References.

6. Logging.


Introduction. Standard Unix System Logging: syslog. Timekeeping: ntp. Configuring Your Site's Logging Security. Application Logging through syslog. Application-Specific Logging outside syslog. Standard System Logging outside syslog. Cross-Platform syslog Alternatives. Log Analysis and Reporting. Best Practices. Online References. Endnotes.

7. Authentication.


Introduction. What Is Authentication? Overview of UNIX Password Authentication. Good Passwords and Bad Passwords. Basic UNIX Password Implementations. Password Cracking. Network Information System (NIS). Alternate UNIX Password Algorithms. Alternate Authentication Schemes. Ssh and Authentication. Integrating with PAM. The ident Server and Authentication. Best Practices. References.

8. Securing a System for Rollout.


You Must Harden the System. Patching: Process and Policy. Why You Must Do More Than Patch. Auditing Services. Secure Network Daemon Replacements. Auditing Passwords. Automating Linux/UNIX Lockdown with Bastille Linux. Automating Solaris?UNIX Lockdown with Other Tools. Best Practices. Resources. Endnotes.

9. Day-to-Day System Management.


Overview. The Proactive Administrator. Reactive Administration. Best Practices. Online References.

II. CRITICAL SUBSYSTEMS.

10. The X Window System.


Introduction. The X Directory Structure. Navigating the X Distribution. Not-So-Basic Basics. Security. Customizing the Environment (as a User). The System-wide X Environment. References.

11. Name Service (DNS).


Introduction. The Client (a.k.a the Resolver). The Name Server. Tools and Troubleshooting. Best Practices. Online Resources.

12. Mail.


The Unix Mail Process. The sendmail MTA Package. Unix Mail Clients. Server Topics. Best Practices. Online Resources.

13. File Sharing.


Overview of File Sharing. Setting Up NFS. Setting Up Samba. Best Practices. Online References.

14. Printing.


Introduction. Printing Spooling System. Printing Under System V. Printing Under BSD. Printing Under LPRng. Printing Under CUPS. Best Practices. Online Resources.

15. Basic Web Services (Server-Side).


Introduction. Providing Basic Web Services. Obtaining and Installing Apache. Configuring Apache. Server-Side Includes. Configuring MIME. CGI Scripts. Adding Features with Apache Modules. Running a chrooted Web Server. References. Best Practices.

16. Backups.


Introduction. Components and Criteria for a Backup. Backup and Restore. Best Practices. Online Resources. Summary.

III. APPLICATIONS AND TOOLS.

17. Open Source Software Management.


Introduction. Building Source Distributions. Managing Your Software Installations. Endnotes.

18. Databases.


Introduction. Databases in General. Choosing a Database Vendor. Oracle Database Overview. Conclusion.

19. Automation.


Introduction. Scripting. Scheduled and Periodic Processes. Automated Configuration Management with cfengine. Tips for Improving Automation Technique.

20. Advanced Web Services.


Providing Advanced Web Services. Scripting Languages. Databases. Languages. Security. After the Fact.

IV. TOWARDS BETTER SYSADMIN.

21. Security.


Introduction. Why Worry? Dangers Presented by Complex Systems. Building a Threat Model. Security Philosophy. Security Is Boring. Configuration Management. Policy. Ethics. Summary. Best Practices. Resources.

22. Intrusion Detection.


Introduction. The Network as a Threat Vector. Network Protocol Concepts. Stacks. Exploiting the TCP/IP Protocol. Positive Signatures. Negative Signatures. Snort. NIDS. Best Practices. Online References.

23. Requirements Analysis and Performance Monitoring.


Requirements Analysis. Performance Monitoring. Capacity Projection and Planning. Best Practices. Online References. Reference.

24. Working with People.


Getting Respect. What Users Want. Being a Proactive Administrator. Dress for Success. Working with Other Admins. Conferences and Associations. Documentation is Good. Management Decisions. Obtaining Needed Resources. Good Syadmins Are Good Humans. You Can't Please Everyone.

V. APPENDICES.

Appendix A. High-Level Installation Steps.


Before You Begin to Install a Machine. Step-by-Step Solaris 8 Installation. Step-by-Step Red Hat Linux 7.1 Installation.

Appendix B. Anatomy of a Filesystem.


Logical View of a Disk. Logical View of Partition. Logical View of a Superblock. Logical View of a Directory. Logical View of a Inode (Regular File). Using the Filesystem: Command Internals. Online References. Endnotes.

Appendix C. User Creation Checklist.


Fast Facts. Checklist.

Appendix D. Binary-Hex Notation Summary.


Introduction. Representation. Collective Nouns. Decimal Representation. Operating on Binary Strings. Subnets, netmasks, and CIDR. Hexadecimal Notation. The Tool at Your Fingertips: bc.

Appendix E. Cryptography in UNIX.


Introduction. Cryptographic Elements. Cryptographic Methods. Secure Communication. Cryptographic Applications. Online References. Books.

Appendix F. Handy Command Kit.


Handy Command List.

Appendix G. Reference Collection.


Periodicals. Mailing Lists. Professional Organizations. URLs. Books.

Index