Mail in a Box just does this as part of its natural installation. It works with a conventional DNS server but, if you point the domain at its internal one, new

Mail in a Box just does this as part of its natural installation. It works with a conventional DNS server but, if you point the domain at its internal one, new email accounts in new domains are up and running automatically. I agree with the other commenter that running BIND is not too difficult but, if you are going to run a server, MIAB is a good way to kill both birds, mail and DNS. Also, the MIAB DNS UI is good.