1 `ext_port`: `<integer> (1 - 65535)` ('default =' `25`)::
3 SMTP port number for incoming mail (untrusted). This must be a different number than 'int_port'.
5 `int_port`: `<integer> (1 - 65535)` ('default =' `26`)::
7 SMTP port number for outgoing mail (trusted).