If your requirement is to enforce any unauthorized means of sending of mail, you can accomplish this by restricting permissions so that no one has permissions to send to anyone accept a few select mailboxes. These select mailboxes will have permissions to send to every user, and can be configured to forward messages to a corresponding distribution group. This is an advanced configuration with a variety of ways the permissions could be applied. Because changing the default permissions could have a negative affect, I would recommend that you test and tweak the permissions in a lab before attempting in production.
There is a straight forward way to restrict who can send inbound mail from the Internet to a specific user or distribution group. The Microsoft Knowledge Base article How to restrict the users who can send inbound Internet e-mail to another user or to a distribution group in Exchange 2003 documents how to set this up.
Do you have comments on this Ask the Expert Q&A? Let us know.
Related information from SearchExchange.com:
Dig Deeper on Exchange Server setup and troubleshooting
Related Q&A from Richard Luckett
Some folders in a mailbox on Exchange Server 2013 are not showing up on the folder list in the OWA virtual directory but do appear in other views. Continue Reading
We have a Client Access Server and Mailbox Server on Exchange 2013 and we want to install an Edge Transport role on another machine. I joined the ... Continue Reading
How can I enable Outlook Anywhere to allow internal use for all users and external use for only some users in Exchange 2013? Continue Reading
Have a question for an expert?
Please add a title for your question
Get answers from a TechTarget expert on whatever's puzzling you.