Problem: Normally a user with a mailbox is allowed to send mails. But if for some reason this should no longer be possible for the user, you have to prevent him from sending mails. Easiest way would be to simply delete his mailbox. But there is another option where you have some extra options on what exactly he is allowed to do or not to do.
Solution: In Exchange 2010 you have to manage such things as delivery or sending restrictions by creating Transport Rules. You can then select lots of different things what the user should be allowed to do with his mail account and how mails will be processed. For example you can block a user from sending mails and delete all his messages and send him a non delivery report. You can redirect mails to a specified mailbox or a group of recipients. Just run the assistant which can be found in the Organisation Configuration > Hub Transport. You will find it on the right side.
Article: The original article can be found here
Jun 30