Delivery Status Notification

A Delivery Status Notification (DSN ) is an e- mail from a mail server to a sender to this teaching of the course of delivery.

DSNs are usually triggered when e- mails are not final deliverable ( "Permanent Failure" ).

It is also usual, intermediate reports on outstanding deliveries if emails temporarily can not be delivered ( "Persistent Transient Failure" ), for example, if the recipient mailbox is full or not a mail transfer agent of the addressee available. This is then followed by some time either a DSN on the final failure of delivery ( "Permanent Failure" ) or a positive DSN about successful delivery ( " Success" ).

A DSN concerning an inappropriate or temporarily undeliverable email is referred to colloquially as a bounce message.

A positive DSN ( " Success" ) is - apart from the case described above - only sent if the sender of the original e -mail has expressly requested, for example, by setting the option " Request delivery " in his e -mail program. Not all e- mail programs, however, offer this option. The positive DSN shows that the e-mail has reached the responsibility of the recipient. Thus, it has the character of a notification of the successful delivery of a throw - writing. As a positive DSN merely confirms the successful placement of the relevant e -mail on the mail server of the recipient, can not be inferred from the receipt of this DSN that the mail in question will actually reach the recipient or will be perceived from this.

Not every mail provider supports DSNs. Usually receives the transmitter when he expects a delivery, when delivered to a mail server which does not support DSNs, a message that is played as a " relayed to non- DSN -aware mailer " - especially when the mail properly has been delivered.

The specifications of the DSNs are defined in RFC 3461 to RFC 3464.