Cisco Cisco Email Security Appliance X1070 Fehlerbehebungsanleitung
What is an email double bounce?
Document ID: 118243
Contributed by Stephan Fiebrandt and Chris Haag, Cisco TAC
Engineers.
Aug 12, 2014
Engineers.
Aug 12, 2014
Contents
Background Information
Background Information
A double bounce occurs when a bounce cannot be delivered. E.g. An undeliverable message is accepted and a
bounce is generated. The bounce itself is sent to a non−existent domain. The bounce will be attempted for
some interval but at some point the Mail transfer agent (MTA) will identify it as not deliverable. Then the
bounce is bounced creating a "double bounce." The double bounce does not generate another email because
the bounce envelope sender was <> so there is no address to which to send the double bounce. Double bounce
action simply eliminates the bounce message that was queued up. (Analogy: where do you return the "return
to sender" postal mail if there is no valid return address? You cannot, so after you figure that out, you just
discard it.)
bounce is generated. The bounce itself is sent to a non−existent domain. The bounce will be attempted for
some interval but at some point the Mail transfer agent (MTA) will identify it as not deliverable. Then the
bounce is bounced creating a "double bounce." The double bounce does not generate another email because
the bounce envelope sender was <> so there is no address to which to send the double bounce. Double bounce
action simply eliminates the bounce message that was queued up. (Analogy: where do you return the "return
to sender" postal mail if there is no valid return address? You cannot, so after you figure that out, you just
discard it.)
The RCPT TO address of a bounce message is the Envelope Sender (aka MAIL FROM) of the original
message. The bounce RCPT TO is not generated from
message. The bounce RCPT TO is not generated from
A double bounce occurs when a bounce cannot be delivered. E.g. An undeliverable message is accepteope
sender (<>) so it cannot be returned to sender.
sender (<>) so it cannot be returned to sender.
Updated: Aug 12, 2014
Document ID: 118243