Everything that someone else could do on an email server that they run for you, they could just as well package into, say, an install CD image, which you

Everything that someone else could do on an email server that they run for you, they could just as well package into, say, an install CD image, which you then could use to run your own functionally equivalent, hopefully well-configured and well-updated, mail server. https://mailinabox.email/ https://mailinabox.email/