Setting a Transport Rule to reply with a Custom DSN for a Disabled User and disconnected mailbox

Question

Here is what I am trying to accomplish. A user leaves the company. We disable there exchange email and that in turn disabled the account in AD. We want a custom NDR to say "This employee is no longer and employee blah blah" We dont get rid of email
boxes but we disable them. 
Here is what I done. Created custom NDR and then created a transport rule to read if the message is sent to [email protected] reply back with this NDR code. It works fine if I disable the user from AD and not exchange. Once I "disconnect" the mailbox
it no longer works. I get the default NDR that says this email cant be found. I don't want that one. I want my custom NDR. I don't want to modify the 5.1.1 message either. Is there away around this?

Answer 1

Hi Nellyjo,
In your case, when you disable the user from AD and Exchange, in fact the message is blocked before reaching transport rule, recipient filtering is blocking this email. If you still want to achieve your goal by transport rule, you need to create a mailbox
or contact to make your transport rule work.
What's more, you also can modify original DSN for external and internal senders to meet your requirement.
For more information, here is a similar thread for your reference.
Setting a Transport Rule to reply with a Custom DSN for a Disabled User
http://social.technet.microsoft.com/Forums/en-US/b1a4dd86-1e0e-43a9-b340-a80352e5c323/setting-a-transport-rule-to-reply-with-a-custom-dsn-for-a-disabled-user?forum=exchange2010
Hope it helps.
If you need further assistance, please feel free to let me know.
Best regards,
Amy
Amy Wang
TechNet Community Support