Exchange 2010/2013 noreply e-mail solution

I have recently came accross the problem. One of my customers had wrong setting of no reply e-mail address and messages got lost between on-premise hub transport servers and Symantec cloud in the way, that it appeared message has been sent successfully, but dropped on Symantec side without notification.

Wrong settings:

All noreply email addresses has been set in MailContact object as follows:, …. and ExternalEmailAddress:

It means that all messages outside the company send from, aliases has been sent with ReturnPath and due to same reason (non existing domain and recipient) messages were dropped.

Solution 1:

  • Change External email address of Mail Contact Object to recipient from existing domain
  • Create transport rule to drop messages to this┬árecipient

Solution 2:

From my point of view very ellegant and easy.

  • Remove Mail Contact object
  • Create DL, enable non authenticated senders to send messages to this DL
  • Assign noreply addresses to this DL
  • Use external e-mail address as primary SMTP address
  • Do not add any members to this DL. This step will cause to drop all incoming noreply messages without notifying anyone.