Ok. Couple of parts to this question.
First, why do messages go to the Unaddressed Messaged distribution list?
The short answer is any time Exchange cannot deliver a message to someone we’ve asked it to, it returns the message to the sender as Non Delivery Receipt (NDR). For subscribers leaving messages for other subscribers this is no problem. If the message can’t be delivered for some reason (Exchange account removed, message store size exceeded etc…) the NDR ends up in the inbox of the person who sent it letting them know it didn’t get there. In the case of an outside caller (i.e. a non subscriber) these messages are left from the “Unity Messaging System” account we create at install time. If the message can’t be delivered, it’s returned to this account as an NDR by Exchange, of course. Every several minutes we check the inbox of this account and if a message is found there, we forward it to the Unaddressed Messaged public distribution list to make sure someone is looking at them.
Second, why can’t you see who they’re addressed to? This one is easy, you can. When the NDR shows up in Example Administrator’s inbox it’s a forwarded message. When you open it, you’ll see another email as an attachment. When you open that email attachment you should see the original message itself, including the person it was originally addressed to and the attached WAV file.
Finally, how to minimize the number of these messages. Well, first we have to find out why they’re not be delivered. There’s a couple of common scenarios I run into fairly frequently. If the subscriber’s inbox is full (as defined in the Exchange administrator) all messages sent to that inbox will bounce back to the sender. Just like if you sent them an email from the desktop, it bounces back at you… works the same for voice mails. Make sure your folks have appropriate message limits defined.
Folks sometimes delete Exchange accounts and leave “stranded” call handlers out there that are set to leave messages for folks that no longer exists which can also result in NDRs like these. Unity 2.4.0 and later has a utility called SysCheck that can find these types of illegal links for you easily. If you’re on a version of Unity earlier than that, you can download the DBWalker utility off my web page which does the same types of checks on your system and reports any inconsistencies for you.
The network being down or a link to one or more other Exchange servers in the site being broken for a period of time can also cause this. The MTA in Exchange will try to get the message to it’s addressed destination for 24 hours, after that it will fail it and send it back as non deliverable.
Finally, I’ve also seen folks use the Unaddressed Messages Distribution list as the primary message recipient for, say, the Operator Box or a public interview box or something. This is a bad idea… this Distribution List is intended to be used only for handling messages left from unknown callers that Exchange could not deliver properly. You might check for this… that would be consistent with you not seeing who the message was addressed to since it was sent DIRECTLY to the unaddressed messages DL.
Hope that helps…
Jeff Lindborg
Unity Product Architect
Active Voice Corp
jlindborg@activevoice.com
