Overview
Sent header details will look a lot smaller than the headers for a received message since it will not consist of the time stamps for the delivery of that message. This is because it hasn’t occurred yet. It will only show how it left the original sending server. Everything beyond the sending of the message will be listed on the received message headers.
Example of a header
There isn’t much information needed from these sent message headers. The sent info does not show the various ‘Received’ lines other than the time stamp of when it was sent along with the contents of the message. It does include the message ID that is applied once it is sent so the mail service provider can track the message if needed.
Reading bounced or undeliverable notification headers
When messages are sent from a DreamHost-hosted email address, and that message is rejected, it will read "Undelivered Mail Returned to Sender". The actual bounce error pointing to why the message was rejected is the information at the bottom of the body of the rejection message. The error message will change depending on why the message was rejected.
The headers of the actual bounce notice are not necessary. When troubleshooting rejected email issues, you want to see the original message headers instead to see how the original message was sent. The headers of the rejection will only show you the details of the message rejection email you received.