I have an application that needs to send (internal) e-mails, so naturally it uses SMTP. Our e-mail server is Microsoft Exchange.

When I look at the e-mails in Outlook, something isn't right with the Sender address. It appears as a proper SMTP address, instead of an Exchange Contact (or something...I have no idea what to call it).

An SMTP exchange looks like this:

220 mail.example.com Microsoft ESMTP MAIL Service ready at Thu, 7 Mar 2013 11:04:41 -0500
250-mail.example.com Hello []
250-SIZE 15728640
MAIL FROM: Adam.Batkin@example.com
250 2.1.0 Sender OK
RCPT TO: Adam.Batkin@example.com
250 2.1.5 Recipient OK
354 Start mail input; end with <CRLF>.<CRLF>
To: Adam Batkin <Adam.Batkin@example.com>
From: Adam Batkin <Adam.Batkin@example.com>
Subject: Test


250 2.6.0 <whatever@smtp.example.com> Queued mail for delivery

But then when I look at the message in Outlook, the sender appears as "Adam Batkin <Adam.Batkin@example.com>" instead of just "Adam Batkin". If I hit Reply, the same thing happens. Let's say the message was sent to a distribution list that I was on, if I hit Reply-All, Outlook doesn't recognize that the sender is my address (which it normally would, if the message didn't come in over SMTP), so my address appears in the To: list of the reply.

Any ideas about how format SMTP messages so that Exchange/Outlook will recognize the senders/recipients as internal users, instead of opaque SMTP e-mail addresses?

  • 1
    It wasn't sent from an internal user. It was submitted via SMTP from an external sender. It doesn't matter that the sender email address matches your internal email address. – joeqwerty Mar 14 '13 at 3:23

A long time ago, Exchange/Outlook did precisely this. Then Microsoft realized it was a security hole and changed it to the current behavior.

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