When sending an email and requesting a "Delivery Receipt" via the checkbox within Outlook (New Message -> Options -> "Request a Delivery Receipt"), a message is generated by the originating Exchange environment that states:
Sender: Microsoft Outlook
Subject: Relayed: Test Message
Message Body: Delivery to these recipients or groups is complete, but no delivery notification was sent by the destination server.
The test message is successfully delivered to the destination.
Environment Layout: Exchange Environment 1 -> Cisco ESA -> Exchange Environment 2
I have full control over all three environments. If I remove the ESA from the environment layout and alter the routing to go direct and repeat the test, I receive the correct response from the destination server per below:
Sender: postmaster@destination_domain.com
Subject: Delivered: Test Message
Message Body: Your message has been delivered to the following recipients:
user@destination_domain.com
Subject: Test Message
There is nothing that I can find in logging to suggest anything has been "dropped/bounced" from either Exchange or the ESA. In the direct connect scenario, there is outbound logging from destination_domain Exchange showing the send events of the Delivery Notification. It's like the ESA is blocking/changing/altering the Delivery Notification request and it's not making it through to the destination.
