Does outMail support NDR (Non delivery report)?
By default outMail does not support NDR (Non-Delivery Reports) because NDRs can be the cause of back-scatter spam. However we at Prolateral appreciate that mail systems like Exchange use NDRs for things like out-of-office replies. As such we can enable NDRs for clients on outMail1000 or greater. To enable this feature we simple need the IP Address/es of your mail server.
However before we enable this feature is it important that your mail server is already setup to reject emails that are being sent to unknown users and thus to further prevent backscatter.
If you are running Exchange 2003 then please see the below article
If you are running Exchange 2007 or Exchange 2010 then please see the article