You could look in the logfiles.
Can someone help me decode the logfiles of possible non-delivered mails? It is about a bulk mailing going out, receiving 452 Too many recipients from mx*.hotmail.com, but also many what I interpret as second delivery attempts seperately afterwards.
I have grepped and awk'ed lists of both the 452'ed addresses and the 250'ed addresses, but both lists contain addresses not on the other list.
So it seems some undelivered mail wasn't delivered succesfully again, but also some mail that didn't throw any errors was somehow sent in seperate attempts rather than collected bulks.
I just want to be able to produce a list of people who didn't receive the mail.