Run an ubuntu LTS makes it pretty easy. There's many guides. Make sure you control DNS that allows you to set MX and SPF records and the like. It's really ju

Run an ubuntu LTS makes it pretty easy. There's many guides. Make sure you control DNS that allows you to set MX and SPF records and the like. It's really just tweaking a few config files after you apt-get install dovecot postfix amavisd clamav. If that sounds scary pay a few $ a month for protonmail fastmail, or one of the others with a decent reputation.