I have an unusual customer request and I can only think of one rather painful way to accommodate it. They want to sever all communications with the outside world for a couple of their domains. In other words, they want all incoming mail to bounce and they want any outbound messages to be blocked in case an employee screws up and replies from the wrong account. The tricky part is that they still want all the mailboxes to be active so that they can refer back to existing data.

Killing inbound is easy as I use a separate mail appliance to manage that piece. Is there an easy way to disable outbound mail for individual domains?