When you receive an NDR(Non Delivery Report) from Exchange the original message will be attached to it. This may be annoying or problematic if the message was large.
It it possible to configure Exchange to strip the “attachment” from the NDR message by configuring the following registry entry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\SMTPSVC\Queuing
Value name: MaxDSNSize
Value type: REG_DWORD
Value data: (value in bytes)
There is some vague documentation of this feature in the following article:
Q323484