How do I completely disable NDR messages in Exchange 2003? I don't want Exchange to send any non delivery reports anymore.
I did already:
From Exchange System Manager, Global Settings, Internet Message Format.
Right click > properties. Advanced tab. Uncheck Allow non-delivery reports.
And restarted Exchange, however this didn't fix it.
The setting you describe will stop NDRs from being sent to the Internet. It won't stop NDRs from being generated and sent to internal recipients. With the setting configured as you described and you attempted to send a non-deliverable message from an Exchange mailbox you would receive an NDR. A remote Internet sender, attempting to send a message to an invalid recipient on your Exchange Server computer, would not receive an NDR, however.