Really depends on what you want to get out of your server. Most easy to use server software I know seems to be geared towards personal use and small organisations.
Mail-in-a-box still works, though last time I checked they were on quite an old Ubuntu LTS release. There are a few pre-packaged docker containers too (i.e. docker-mailserver) which seem to be popular. I myself use Mailcow, but that's pretty heavy for "just" a mail server.
There's also a mail server that I can't for the life of me remember the name of, which packaged a whole bunch of stuff into one single binary you can run rather than use the classic "every part of the email delivery chain is a separate process" approach. I think it was written in Go?
> There's also a mail server that I can't for the life of me remember the name of, which packaged a whole bunch of stuff into one single binary you can run rather than use the classic "every part of the email delivery chain is a separate process" approach. I think it was written in Go?
I personally use docker-mailserver https://docker-mailserver.github.io/docker-mailserver/latest... because it's a pretty traditional stack (postfix+dovecot+sieve etc) just already containerized and configured, so there's a lot of info already out there on how it works
The number 0 requirement that you have to solve regardless of stack though is to get an IP with a good reputation. I've got Comcast Business to my apartment, which I think is probably the best way to get a good IP since it's relatively difficult for spammers to have used it in the past. Alternatively, relay everything through Mailgun/SES/whatever
For a business? You don't. For hobby/fun? I still wouldn't. I tried years ago and you're just going to fight blacklisting constantly. If you're on a residential/consumer internet service, trying to set it up in your home lab, forget it.
I remember Mail-in-a-Box being popular at one point, wondering if that's still the case.