Sending an email with the header return-path using windows virtual mail server

Question

I\'m trying to send an email message using the .NET MailMessage class which can also have the return-path header added so that any bounces come back to a different email add

Answer 1

The Return-Path is set based on the SMTP MAIL FROM Envelope. You can use the Sender property to do such a thing.
Another discussion on a related issue you will have sooner or later: How can you set the SMTP envelope MAIL FROM using System.Net.Mail?

And btw, if you use SmtpDeliveryMethod.PickupDirectoryFromIis, the Sender property is not used as a MAIL FROM; you have to use Network as a delivery method to keep this value. I did not find any workaround for this issue.
PickupDirectoryFromIis, Sender property and SMTP MAIL FROM envelope