To meet the requirement of forwarding mail to an external email address, it can be done by creating a forwarding rule in user's mail DB (mailfile) .
However, it requires that Administrator first opens the mail DB of the user.
If forwarding address field of user's person document is used, then the user would not receive the mails in his inbox.
The customer's requirement is that the Mail administrator should be able to make settings at the backend for one or more users such that:
1. The user continues to receive the mails in his inbox.
2. Forwarding also takes place to the specified email address.
3. Admin does not have to open the corresponding user's mailbox (which happens if mail rule is to be created).