i will fix your SMTP server in such a way that it enables you the right send outgoing e-mail messages through the SMTP server, and that when a outgoing mail is not deliverable it sends back the e-mail messages back to the sender.
i will configure your e-mail client in such away that it knows what SMTP server to use for sending outgoing e-mail messages, i.e configuring your e-mail client to access the SMTP (outgoing mail)server.
