@swist Running a mail server is a pain. I have a few and have been doing it for years. If you are not going to go full blown you might consider using one of the hosted mail providers that can provide incoming and outgoing email services like Mandrill, etc.
Now, if you really want to dig in and run your own, my recommendation is to use iRedMail (http://www.iredmail.org) and set up one on a blank ubuntu server. You could start with the forge one, not sure if the installed packages will interfere with the install script for iRedMail.
I used to set up my servers piece by piece. This makes it a million times easier and you end up with a more secure and reliable server. I have 5 of them in production right now.