About This Manual

This is the User Guide for the KumoMTA SMTP server. For license information, see the Legal Notices.

This guide assumes familiarity with SMTP and general email infrastructure concepts. It does not teach you how to use your operating system or command-line interpreter.

KumoMTA is under constant development, and this documentation is updated frequently.

If you have questions about using KumoMTA, community support is available in the Forum and the Community Discord.

Typographical and Syntax Conventions

This manual uses certain typographical conventions:

Note

This is a noteworthy section

Warning

This indicates a warning

Danger

This indicates something that can have dangerous consequences

Text in this style indicates input that you type in examples.

Text in this style indicates the names of executable programs and scripts, examples being kumod (the KumoMTA server executable).

Text in this style is used for variable input for which you should substitute a value of your own choosing.

Text in this style is used for emphasis.

Text in this style is used in table headings and to convey especially strong emphasis.

Text in this style is used to indicate a program option that affects how the program is executed, or that supplies information that is needed for the program to function in a certain way. Example: “The --policy option tells the kumod server the path to the initial policy file to execute on startup”.

File names and directory names are written like this: “The simple-policy.lua file is located in the /etc/kumod directory.”

Character sequences are written like this: “To specify a wildcard, use the ‘%’ character.”

Commands that you type at a shell prompt are shown in a console code block, prefixed with a $ prompt:

$ type a command here

Commands that must be run with elevated privileges are shown using sudo:

$ sudo type a command as root here

KumoMTA command-line tools, such as kcli, are also invoked from the shell prompt:

$ kcli type a KumoMTA CLI command here

Where it is useful to show the result of a command, the output either follows the command in the same block or appears in an adjacent txt block.

Commands are issued in your command interpreter. On Unix, this is typically a program such as sh, csh, or bash.

Note

When you enter a command shown in an example, do not type the $ prompt shown in the example.

In syntax descriptions, square brackets (“[” and “]”) indicate optional words or clauses. For example, in the following statement, --user is optional:

kumod--policy simple-policy.lua [--user] someuser