In the event of your journal mailbox going offline, any journal reports destined for these mailboxes will queue. After two days (though this time is the expiry time for messages in your Exchange organization, so may be different) the message will expire and an NDR sent to the sender of the journal report. The problem is that the journal report was not sent by anyone – the From address is <>. So no NDR is generated and the journal report is lost.
There is the JournalReportNdrTo property of TransportConfig that allows you to set who will receive these NDR’s.
Set-TransportConfig -JournalingReportNdrTo email@example.com
Once this value is set this mailbox should be monitored occasionally and any NDR’s opened and the containing message (the journal report) resent so that it goes back to the (now working) journal mailbox.
In Exchange 2013 this NDR mailbox is never the subject of journaling nor do any inbox rules run against this mailbox – even if this mailbox is mentioned in a journal rule of if the mailbox has inbox rules associated with it. When you set this value in your Exchange 2013 organization you get the following warning:
WARNING: Any mail to JournalingReportNdrTo mailbox will not be journaled and it will not honor transport and mailbox rules settings. It is recommended to create a dedicated mailbox for JournalingReportNdrTo setting or set it to an external address.
Or if you set it in Exchange Control Panel then the following popup appears:
The warning also mentions that Transport Rules do not fire for this mailbox, but that is not what I have seen – though it might be that specific transport rules do not get actioned, but others do. Inbox rules and Journal Rules are not processed.
Therefore it is very important that you do not use a standard mailbox as the target for JournalReportNdrTo, as this mailbox will have all its outbound emails missing from any journal it should be stored it (and this would be a compliance issue) and the user will get bothered that their email rules in Outlook are not working.
The problem is that this is not the case in Exchange 2010, so if you have set the JournalReportNdrTo property in the past on a mailbox, and then migrated that mailbox to 2013 you will not be warned, but you will find that upon migration to 2013 your inbox rules stop working and if you look in the journal mailbox you will not find messages send from this mailbox. Therefore create a mailbox specifically for journal NDR’s before you migrate to Exchange 2013.