I have a mixed environment with 1x Exchange 2003 and 1x Exchange 2010 server.
everything works fine with the exception of NDR (non-deliverable replies).
I have an internal connector betwen the 2 Exchange server with the below mail flow:
User sends email ==> Exchange 2010 ==> Exchange 2003 (Mail.company.com) ==> internet
external internet user sends email ==> (mx record: mail.company.com) smtp/perimeter server w/ antispam/antivirus software ==> Exchange 2003 ==> exchange 2010 ==> recipients
When I'm checking the queue vis System Manager, I often notice a connection queue for Mail.company.com with emails sending from firstname.lastname@example.org...within the queue the emails look like it's returning NDRs but it's stuck in the queue because the email addresses are adding the "mail" to the domain, i.e. User@mail.company.com.
So I'm thinking there's a setting somewhere that i need to change so that when postmaster is replying, that the emails will be sent to email@example.com.
Any clue where I might need to change this?