FreeBSD mail server: IMAP using Dovecot

This is a follow-up post to the initial FreeBSD mail server article that I posted a few weeks ago. In this step, we will build upon what we set up in the first part and add the possibility to fetch email from a mail client using IMAP. We will still use system users for authentication, before we switch to virtual users in the next step. In this series we will set up a fully-featured mail server in a FreeBSD jail using OpenSMTPd, Dovecot and rspamd.