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Read and Delivery Receipts Mystery

Posted by IT Intern on September 1, 2009

Today the CEO came to us with an unusual problem. Despite his Outlook 2007 being set to never send read receipts, he was constantly finding read receipts in his Sent folder to an overseas customer. For whatever reason, he does not want to correspond with the customer, and is understandably upset that, after failing to reply to the customer’s emails, the customer will then email back stating he *knows* he got the email and demanding a reply.

So I opened up Outlook 2007 and sent myself several messages, while changing Outlook settings between each. I found what you would normally expect: When I have my “respond to requests” settings on “Always send a response,” I would get a receipt. When set to “Never send a response,” I wouldn’t get one. And when set to “Ask me before responding,” it would do whichever option I chose.

I tried to find if there is any way for a sender to force a recipient to send a read receipt, and as far as I could find, there is not.

Seemingly unable to reproduce his problem, I asked my boss to show me the copy of the sent read receipt that he had forwarded. It did not look at all like the read receipts I had sent myself. In fact, it looked more like a delivery receipt. Checking the headers of the received message confirmed: the messages contained both the


header for a read receipt request, and the


header for a delivery receipt request.

The weird thing is, though, that delivery receipts are supposed to be handled by the server, not the client, yet he had those delivery receipts right there in his Sent folder. We promptly disabled delivery receipts on our server, and began sending each other test messages. As we expected, no delivery receipts. How could we reproduce this problem? We decided to re-enable delivery receipts and sent some more tests so we could examine the headers. At this time, we sent one of our test messages to the CEO’s account, and to our surprise we got TWO delivery receipts back.

Thoroughly confused, we at first wondered if Outlook wasn’t sending its own delivery receipts (although if it was, we should have gotten them from each other as well), until a closer look at the header of the second delivery receipt revealed the culprit: his Blackberry was sending the delivery receipts itself.

Of course, by this point he had been out of the office for hours, so first thing in the morning we’ll change his Blackberry settings and send him another test email.

Hopefully this will solve his stalker-customer woes 😉

Update: Apparently, there is no Blackberry setting that will disable sending delivery receipts, and this seems to have been a known problem since at least 2007. See these forums

We’re trying to implement a filter to catch any email with the “Return-Receipt-To” header and strip it before it gets delivered, but a better option might be just to switch to an iPhone. 😀

Second Update: Stripping the header worked. Our own server would still send a delivery receipt even with the header stripped, but without the header the Blackberry did not know to send one, so it doesn’t now. Problem solved, except anyone who has already received a delivery receipt from his (or anyone’s) Blackberry now has his Blackberry’s direct address (if they know enough to look at the headers). Such a pain, and he’s considering switching to an iPhone anyway.


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