[dig1]

Running mail isn't hard if you know a few bits about how things work. As a matter of fact, if correctly set, it can be left running for years without significant time investment. But I'm getting the impression that anything that can't be set in 2 clicks is hard for a particular HN crowd.

[c0balt]

The setup of a mail server is not very hard. An intermediate to beginner admin can do it.

On of the hardest parts is spam filtering both for incoming and outgoing traffic. In particular outgoing, so, e.g., a compromised or malicious user, can have harsh repercussions by big providers like M$ (Outlook) and Google. You can find a myriad of stories just on HN about these platforms literally not even allowing you to apply for access after an incident happened.

And your users won't care that M$, Google or Yahoo behaves like this, they will only care about their emails not being delivered by/ to you.

I had an internship at $company that offers manages hosting for Email along with web shops. The technical setup is the easier part of the business.

[charcircuit]

There is a difference between running mail for yourself and running mail as an open provider for others.

[MuteXR]

Your tiny Postfix server is nothing compared to what large scale mail hosting entails.