The “Microsoft Exchange” is a special recipient object that provides a message sender that differentiates system-generated messages from other messages. It is like an internal postmaster. We are all familiar with the message sender named “System Administrator” in previous versions of exchange. For example, you get an email from “System Administrator” if the recipient mailbox is full. In Exchange 2007, the “System Administrator” has been replaced by "Microsoft Exchange" as the sender. Microsoft Exchange recipient sends different types of messages like DSN messages, quota messages, journal reports etc. Have a close look at the screenshot below & you will understand what I am talking about.
The Microsoft Exchange recipient is used as the sender for system-generated messages that are sent to internal users only. When system-generated messages are sent to an external sender, the External Postmaster address is used as the sender of the message. ExternalPostmasterAddress parameter ca be configured using the Set-TransportServer cmdlet.
By default, messages that are sent to the Microsoft Exchange recipient are discarded. It can be good and bad, depending upon your network. For example, a user receives a DSN message from “Microsoft Exchange” and if he/she is intelligent enough to forward the messages from “Microsoft Exchange” to your helpdesk than replying to the email received, you are safe. You can always configure an email address for the Microsoft Exchange recipient and have it monitored, in case one of your users decides to reply. The reply address for “Microsoft Exchange” can be set in Organization Config. By default, it is not set. Run Get-OrganizationConfig to find out.
MicrosoftExchangeRecipientReplyRecipient parameter specifies the recipient that should receive messages that are sent to the Microsoft Exchange recipient. Run the following command to configure a reply address.
Set-OrganizationConfig –MicrosoftExchangeRecipientReplyRecipient “emailaddress”
Now you don’t have to worry that emails sent to the Exchange Recipient will be discarded!