Sometimes, you want a backup mail server. Something that will accept mail and hold it for delivery until your primary mail server is available again. This is the purpose of a backup MX (the MX refers to the type of DNS record that mail exchangers use).
If you’re looking for a policy server that includes greylisting, PolicyD is a solid choice.
Roundcube is one of the better webmail solutions.
This covers the setup of h2o, PHP, phpPgAdmin, and PostfixAdmin.
This covers the setup of SSL (CA, keys, and certs) for the services we will run, and also the PostgreSQL database.
This is a multi-part article. There are too many components to fit all of them into a single writeup. The first part will cover the FreeBSD install and initial setup of the OS.