Gets the DSN gateway type.
A string representaion of the message gateway type from "DSN-Gateway" DSN field, or a null reference (Nothing in Visual Basic) if no such field contained in the DSN.
This field indicates the type of the gateway or MTA which translated a foreign (non-Internet) delivery status notification into this DSN. This field MUST appear in any DSN which was translated by a gateway from a foreign system into DSN format, and MUST NOT appear otherwise.
In this example, DSN field is:
DSN-Gateway: dns; gateway.home.local
The return value is marked bold.
DsnAttachment Class | MailBee.BounceMail Namespace | DsnGatewayName