Why would a sent Item have header info . Exchange 2016 , outlook 2016

Question

Hi all .

To my knowledge, there are no header for sent items for generally user mailbox in outlook Typically, the Sent Items folder is only used to save a copy of a send mail.

But I have one of my user asking me why one of their sent items has header information display .

Trying to do some research but Not getting much , except Typically this is not the case .

But

Now I seen this with Share mailbox , As we define these two attitudes for those type of mailbox

-MessageCopyForSentAsEnabled $True
-MessageCopyForSendOnBehalfEnabled $True

Due this a copy get sent to the Shared Mailbox sent items folder , thus it's transfer via Exchange 2016 server and header are attached and do display header info

Are there any other situation where a sent Items email would have header ?

Inbox Rules
Delegations

Thanks
Dean

Answer 1

I can't think of any.

Answer 2

Hi @Dean Maher ,

Based on my knowledge and research, agree on that "typically this is not the case". By default, the message header won't show up for mails we send out.

Then I tried checking the mail attributes using the MFCMAPI tool and found that the internet message header is corresponding to the PR_TRANSPORT_MESSAGE_HEADERS property of a message. According to this link for the property, the message header information is generated for inbound messages. So my understanding is that, basically it's not possible that the message with message header is a mail sent out from the user's mailbox.

With the above being said, considering that only one of their sent items has header information display, I am assuming perhaps it's actually a received message, but moved to the sent items folder by accident or any inbox rule.

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