How can I enable non-delivery reports (NDRs) to external mail senders in Exchange 2003?

The automatic non-delivery reports (NDRs) in reply to emails sent to non-existing addresses in your organisation are a feature of Exchange and POPcon does not interfere with them. You can enable or disable NDRs using your Exchange System Manager:

1. Open the Exchange System Manager at Global Settings > Intenet Message Formats and right-click on "Standard" coming up on the right-hand pane, then chose "Properties".

   

2. Check or uncheck "Allow non-delivery reports".