Just a heads up, I ran my own SMTP server for a couple domains for a number of years back in the 2010’s and honestly deliverability was always a nightmare since I wasn’t big enough to get my own IPv4 allocation so I ended up using IPv4 addresses that the VPS provider had, and those had serious reputation issues that I had to clean up. Eventually I closed down those business relationships so that I could stop hosting, and eventually set up my SMTP server to be receive only, and pushed all my mail out via Amazon SES (via configuration in my mutt config). Really it was so I could use procmail for filtering and then also have some very tight reject rules at the MTA (mail transfer agent) so I could block spam.

I mean it worked, but it was only for my personal use.

I ran FreeBSD 7 machines with plain old sendmail (yikes!) and dovecot, but at some point I transitioned over to postfix when the configuration got more complicated. I think it was moving to maildir that caused me to move from sendmail to postfix

Once upon a time I was a senior tech lead at an email service provider, and I know enough to know that rolling your own is a very big lift thanks to the email mafia.

Some recent jwz posts:

• Today in Email Hegemony
• The oligopoly has won.
• Today in “Google broke email”.