[Mailman-Users] Postfix->Mailman->Exchange - Where are my NDR's?

[Lamaster, Robert]

I need some help tracking down where my NDR's are going.  So far, we
haven't seen any.  Here's the setup for how mail is set to our lists:

User sends to a M$ Exchange mailbox (Created in Active Directory).  That
mailbox is configured to forward to a "Contact" in Active Directory,
which has the email address of the list on Mailman.  Postfix receives
the message from the "Contact" and hands it off to Mailman, which
dutifully expands it to individual emails (with VERP) as list-bounces.
Mailman then uses M$ Exchange as it's MTA to send the mails to (1)
internal recipients, and (2) our front-end Exchange server for delivery
to external recipients.

 

So... we've checked the inbox for the sender's mailbox and the M$
Exchange mailbox (there isn't a mailbox for the contact) and have found
no NDRs, even though we know there are a ton of them being generated.
Are the NDRs being returned to Mailman?  If so, is there any way I can
intercept them?