For mail administrator,always do not have too much time to check whether user sending normal email or spams.So the NDR is very important to administrator,how the administrator can get a copy of all NDR generated by Xeams?

In that case,administrator can easily find out what cause the mail delivery failture and do action.

Take a look at ndr.log, which contains a log entry for both generated NDRs as well as received NDRs from other servers.