Mac OS X Unleashed

By John Ray and William C. Ray

• Table of Contents
  • Copyright
  • About the Author
  • Acknowledgments
  • Tell Us What You Think!
  • Introduction
  • Part I: Introduction to Mac OS X
  • Chapter 1. Mac OS X Component Architecture
  • Chapter 2. Installing Mac OS X
  • Chapter 3. Mac OS X Basics
  • Chapter 4. The Finder: Working with Files and Applications
  • Chapter 5. Running Classic Mac OS Applications
  • Part II: Inside Mac OS X
  • Chapter 6. Native Utilities and Applications
  • Chapter 7. Internet Communications
  • Chapter 8. Installing Third-Party Applications
  • Part III: User-Level OS X Configuration
  • Chapter 9. Network Setup
  • Chapter 10. Printer and Font Management
  • Chapter 11. Additional System Components
  • Part IV: Introduction to BSD Applications
  • Chapter 12. Introducing the BSD Subsystem
  • Chapter 13. Common Unix Shell Commands: File Operations
  • Part V: Advanced Command-Line Concepts
  • Chapter 14. Advanced Shell Concepts and Commands
  • Chapter 15. Command-Line Applications and Application Suites
  • Chapter 16. Command-Line Software Installation
  • Chapter 17. Troubleshooting Software Installs, and Compiling and Debugging Manually
  • Chapter 18. Advanced Unix Shell Use: Configuration and Programming (Shell Scripting)
  • Part VI: Server/Network Administration
  • Chapter 19. X Window System Applications
  • Chapter 20. Command-Line Configuration and Administration
  • Chapter 21. AppleScript
  • Chapter 22. Perl Scripting and SQL Connectivity
  • Chapter 23. File and Resource Sharing with NetInfo
  • Chapter 24. User Management and Machine Clustering
  • Chapter 25. FTP Serving
  • Chapter 26. Remote Access and Administration
  • Chapter 27. Web Serving
  • Part VII: Server Health
  • Chapter 28. Web Programming
  • Chapter 29. Creating a Mail Server
    • Running a Mail Server
    • Activating Sendmail
    • Sendmail Configuration
    • University of Washington imapd
    • Web-Based E-mail
    • Summary
  • Chapter 30. Accessing and Serving a Windows Network
  • Chapter 31. Server Security and Advanced Network Configuration
  • Chapter 32. System Maintenance
  • Appendix A. Command-Line Reference
  • Appendix B. Administration Reference

Running a Mail Server

The first step in running a successful e-mail server is determining that you actually need an e-mail server. Unlike more basic services, such as Apache, e-mail is a more intrusive process that enables complete strangers to store information on your computer. In addition, administration of an e-mail server is an ongoing process. Monitoring and detecting problems is a must. Sendmail has been around for more than 20 years, but it's still growing and evolving. Because it is one of the most highly utilized pieces of software on the Internet, it is also one of the most prone to attacks.

Mail server security is unlike basic server security because it occurs on two levels. First, you must protect the physical server software from being exploited. Remote users have found numerous holes in earlier versions of Sendmail that granted root access to the e-mail server, or enabled them to gain other forms of unauthorized access. Monitoring server logs for unexplained connections and abnormal mail transmissions is standard practice. This aspect of mail server security should seem familiar, because it should be a common practice for other basic system services, such as FTP or HTTP.

The second security problem is mail server abuse. This doesn't necessarily equate to compromising the e-mail server, but the results can be even more far reaching. E-mail spam, for example, is the result of poorly implemented e-mail security. In the case of spam, there are two possible problems. The first is an authorized user is inappropriately using your e-mail resources; the second is an unauthorized user is taking advantage of an open relay on your mail server to do the work of distributing his or her spam.

In either case, the result is the same. The second scenario is the most serious when considering the security of your network. It is very much akin to hacking, but without necessarily needing to exploit any program flaws on your system.

For these reasons, you should seriously consider alternatives to running your own mail server. Users in need of controlling their own e-mail accounts, the privacy of storing their own messages, or requiring complex mail relaying or automated processing, are the best candidates for running their own server.

A properly configured server requires little maintenance and will perform extremely well on Mac OS X. An improperly configured server, however, could be a disaster.

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