Disposition-Notification-To

When the Disposition-Notification-To header field is present, a request for a MDN (Message Delivery Notification) is made. The recipient's email software (Outlook, Eudora, etc.) may silently ignore the request, or it may prompt the user for permission to send the MDN. There is no guarantee of the "return-receipt". The Disposition-Notification-To header field is the de facto standard for requesting return-receipts (i.e. MDN, or message delivery notifications).

Again, most e-mail software (Outlook for example) asks for consent via some sort of prompt or dialog box, or globally through the user's setting of a preference. The user might also indicate globally that MDNs are to never be sent or that a "denied" MDN is always sent in response to a request for an MDN. The Disposition-Notification-To header field should specify the email address where the MDN is to be delivered.

If there is a Return-Path header field present in the email, the email address specified should be identical to the email address specified in Disposition-Notification-To, otherwise confirmation from the user is (usually) forced and in some cases the MDN is dropped altogether. Emails with Disposition-Notification-To should also have a Message-ID header to enable automatic correlation of the MDN with the original message.

Example:

Disposition-Notification-To: notification-address@chilkatsoft.com