Part IV: Reference

The fourth part of this tutorial provides a comprehensive reference for all the innerworkings of the configuration file, and for debugging and rule testing.

• The Configuration File
• Presents an overview of the sendmail.cf file. Comments, joined lines, and the V configuration command are detailed.
• Rules
• Shows how the workspace is rewritten by individual rules. Operators, like $*, are explained here.
• Rule Sets
• Covers the flow of addresses through rule sets, and illustrates the special uses of rule sets 0 through 5, and the check_ rule sets.
• Delivery Agents
• Shows how to define mail delivery agents with the M configuration command. The F= flags are also listed.
• Defined Macros
• Shows how to define and use macros. An explanation of all macros currently in use is included.
• Class Macros
• Shows how multiple values can be stored in class macros. The special uses of the $= and $~ prefixes are also shown.
• Database Macros
• Shows how to create, declare, and use external databases and network maps.
• Options
• Shows how to declare options from the command line and in the configuration file. Then every option is explained.
• Headers
• Describes the legal contents and form of headers in email messages and in the H configuration command. Then many common headers are explained.
• The Command Line
• Shows the many ways to run sendmail with emphasis on its numerous command-line switches.
• Debugging with -d
• Documents the many debugging switches available with sendmail.
• Rule-Set Testing with -bt
• Describes sendmail's rule-testing mode and shows the many ways to use that mode to solve problems.