Gets the type of the MTA from which the message was received.
A string representaion of the message transfer agent type from "Received-From-MTA" DSN field, or a null reference (Nothing in Visual Basic) if no such field contained in the DSN.
The Received-From MTA is the MTA from which the Reporting MTA received the message, and accepted responsibility for delivery of the message.
In this example, DSN field is:
Received-From-MTA: dns; host.home.local
The return value is marked bold.
DsnAttachment Class | MailBee.BounceMail Namespace | ReceivedFromMtaName