kumo.on('get_listener_domain', function(domain, listener, conn_meta))

This event is triggered by the SMTP server to retrieve information about either a source or destination domain to help determine whether the message should be accepted/logged/relayed.

The listener parameter is the listener endpoint on which the message is being delivered. You can use this to vary behavior depending on the listener address.

When the SMTP RCPT TO command is issued by the client, the destination domain is passed as the domain parameter to this event.

Since: Version 2023.08.22-4d895015

The functionality described in this outlined box requires version 2023.08.22-4d895015 of KumoMTA, or a more recent version.

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The conn_meta parameter represents the connection metadata and can be used to share state between the various SMTP listener event handlers. See Connection Metadata for more information.

The event is expected to return a listener-domain object constructed by a call to kumo.make_listener_domain, or a nil value to indicate that there is no explicit configuration.

If none of log_relay, log_oob or log_arf are set to true, in the returned listener-domain object, then the RCPT TO command is rejected.

Once the DATA stage has transmitted the message content, and after the smtp_server_message_received event has been processed, and the reception logged (which is where OOB and FBL data is parsed and logged), the recipient domain is passed to this event as the domain parmater. If relay_to is false in the returned listener-domain object, then the message will not be spooled and that will be the end of its processing.

See kumo.make_listener_domain for some more examples.