In normal operation it should not be necessary to call this method explicitly. It is used to implement other methods and may be useful for testing private extensions. The hostname argument defaults to the fully qualified domain name of the local host. In normal operation it should not be necessary to call this method explicitly. The hostname argument defaults to the fully qualified domain name of the local host.
Case is ignored.
Otherwise returns an SMTP error code of 400 or greater and an error string. The SMTP does not modify the message headers in any way. This method will return normally if the mail is accepted for at least one recipient. Otherwise it will throw an exception. That is, if this method does not throw an exception, then someone should get your mail.