Answer
Look for Alert number 8501 which is of the form:
message sent transitory QSXRDJSF@dev1.dom (postmaster@dev1.dom) user1@dev1.dom 14274946800001@user1.dev1.dom
This message was sent by transitory address QSXRDJSF@dev1.dom (postmaster@dev1.dom) to user1@dev1.dom. The message id was 14274946800001@user1.dev1.dom.
In this example postmaster@dev1.dom sent the message using the transitory address QSXRDJSF@dev1.dom
See Also:
Keywords:transitory address