

The question has to be asked: If you do not already know all of that or at least have a good understanding of it all then what on earth makes you think you’re in any way qualified to run a mail hosting service?
It’s like asking how to setup and run a car repair and maintenance shop when all you know is how to change a tire.
You would perhaps be better off reselling someone else’s service (for instance: Office 365 reseller) and actually learn how to run a mail service that at least has training wheels and competent help readily available.
“I’ve seen spam you people wouldn’t believe. Routers on fire off the OCs of AGIS. I watched MXes burning in the dark near the Cyberpromo Gateway. All those moments will be lost in time, like tears in rain. TTL=0.”