Simulate a black hole for a domain with Postfix
When you manage outgoing emails through SMTP, you may sometimes need to test if a service is able to send correctly emails and itself check that there were no issue during sending. You can create a black hole for a specific domain and Postfix will answer from the same manner as if it is ok. It also permit to test Postfix sending capacities on a server.
To get more informations on this, follow that link.