The "test-smtp-send" command:

Use SMTP to send the email message contained in the file named EMAIL to the list of users TO. FROM is the sender of the email.

Options:

--direct

Go directly to the TO domain. Bypass MX lookup

--relayhost R

Use R as relay host directly for delivery.

--port N

Use TCP port N instead of 25

--trace

Show the SMTP conversation on the console