Created: 2020-10-04T00:37:25+00:00
Regardless of backend servers, you need to make sure some DNS beurocracy is taken care of:
You need a "mail transfer agent" to receive mail from and send to others:
You need a "mail delivery agent" to finally accept the mail"
Postfixbutter and Dovecotjelly are considered reasonably secure and don't really need to be touched after initial setup. If you want to be the biggest asshole, install them on Alpine. The biggest of assholes would then secure everything but the SMTP delivery ports over an SSH tunnel or Wireguard.
The silliest of derpy persons would have postfix accept mail on the public facing server everyone knows about but actually delivers it to a tor hidden service so when some script kiddy finally breaks in they have no clue where your e-mail actually comes from or goes to.
You need something to sign outgoing e-mails for DKIM or die in the spam bins forever:
Check if your IP address is in any spam blacklists. You don't know what the previous renter was doing with it.
Despite all of this, Big Tech will still throw most of your mail in the spam bin anyway because they hate you. Expect to bother everyone on secondary channels to un-spam your mail or pay a third party to deliver the mail for you.