Additional Resources

Installed Documentation

The documentation on your system is a good place to start looking for additional configuration options for TCP Wrappers, xinetd, and access control.

• /usr/share/doc/tcp_wrappers-<version>/ - This directory contains a README file that discusses how TCP Wrappers work and the various hostname and host address spoofing risks that exist.

• /usr/share/doc/xinetd-<version>/ - This directory contains a README file that discusses aspects of access control and a sample.conf file with various ideas for modifying service-specific configuration files in the /etc/xinetd.d/ directory.
• TCP Wrappers and xinetd-related man pages - A number of man pages exist for the various applications and configuration files involved with TCP Wrappers and xinetd. The following are some of the more important man pages:

  Server Applications

  • man xinetd - The man page for xinetd.

Configuration Files

• man 5 hosts_access - The man page for the TCP Wrappers hosts access control files.

• man hosts_options - The man page for the TCP Wrappers options fields.
• man xinetd.conf - The man page listing xinetd configuration options.

Useful Websites

• http://www.xinetd.org/ - The home of xinetd, containing sample configuration files, a full listing of features, and an informative FAQ.

• http://www.macsecurity.org/resources/xinetd/tutorial.shtml - A thorough tutorial that discusses many different ways to optimize default xinetd configuration files to meet specific security goals.

Related Books

• Hacking Linux Exposed by Brian Hatch, James Lee, and George Kurtz; Osbourne/McGraw-Hill - An excellent security resource with information about TCP Wrappers and xinetd.