Suppose you have the following situation: an Exchange 2000 server hosts multiple mail domains, e.g. domain1.com, domain2.com,domain3.com. The Exchange server is a member of the Active Directory domain ad.domain0.com. If the Exchange server generates a Non-Delivery Report, for example because someone has sent a message to wrongaddress@domain2.com, then the sender address of this NDR is always postmaster@ad.domain0.com. RightPostmaster for MS Exchange 2000 application can correlate NDR with domains, so that a NDR related to domain2.com will be sent from postmaster@domain2.com, and a NDR related to domain3.com will be sent from postmaster@domain3.com. Application is a transport event sink.