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
    • Security-Minded Thinking
    • What Is Secure Shell?
    • Starting SSH in OS X
    • Using SSH: From Unix Box to Unix Box
    • Using an SSH2 Client in Mac OS
    • Using an SSH1 Client in Mac OS
    • Public Key Authentication
    • Are There Any Graphical SSH Clients for OS X?
    • Are There SSH Clients Available for the PC?
    • Summary
  • Chapter 27. Web Serving
  • Part VII: Server Health
  • Chapter 28. Web Programming
  • Chapter 29. Creating a Mail Server
  • 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

Starting SSH in OS X

If you are running the first non-public beta release of OS X, SSH is not included. Run Software Update, which is located in System Preferences, to get the update (patch) that includes SSH. The first official release that contains SSH is OS X 10.0.1. Software Update places your SSH server, sshd, in /usr/sbin and your SSH tools in /usr/bin.

After you have SSH installed, you are ready to turn on your SSH service. Just go to the Sharing pane in System Preferences and check the Allow Remote Login option, as shown in Figure 26.1. The first time you do this, you might experience a delay.

Figure 26.1 Check the Allow Remote Login box in the Sharing pane to start the SSH service.

One of the main activities that checking this box performs is updating your /etc/hostconfig file, shown following this paragraph, to indicate that the SSH service should be turned on. Note that SSHSERVER is set to YES. If you were to turn off the service, this would revert to NO. Because this file has the comment that it is maintained by the system control panels, it might not be wise to edit this file directly yourself. However, it is interesting to be able to occasionally see some of what the operating system is doing for you behind the scenes.

##
# /etc/hostconfig
##
# This file is maintained by the system control panels
##
# Network configuration
HOSTNAME=-AUTOMATIC-
ROUTER=-AUTOMATIC-

# Services
AFPSERVER=-YES-
APPLETALK=en0
AUTHSERVER=-NO-
AUTOCONFIG=-YES-
AUTODISKMOUNT=-REMOVABLE-
AUTOMOUNT=-YES-
CONFIGSERVER=-NO-
IPFORWARDING=-NO-
MAILSERVER=-NO-
MANAGEMENTSERVER=-NO-
NETBOOTSERVER=-NO-
NISDOMAIN=-NO-
TIMESYNC=-YES-
QTSSERVER=-NO-
SSHSERVER=-YES-
WEBSERVER=-NO-
APPLETALK_HOSTNAME=creampuf

If you check your process listing for ssh, you will now see an sshd process:

[localhost:~] joray% ps aux | grep ssh

     root    614   0.0  0.0     1476    340  ??  Ss     0:00.50 /usr/sbin/sshd
     joray   676   0.0  0.0     1384    300 std  S+     0:00.01 grep ssh

For the 10.0.1 update, what you have just turned on is the open source package SSH package, OpenSSH -2.30p1. It is SSH1- and SSH2-capable. Because it supports both protocols, a connection from either type of SSH client works.

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