Email system requires multiple components to work together. Here are the overview of incoming and outgoing mail flows on the server.
It’s too complicated to set up everything at once, so the articles explain step by step, starting from minimum.

  • The details may not be accurate to make things simpler

Incoming mail flow

  • Scan emails with Rspamd to reject/quarantine spam and virus.
Incoming Mail Overview

Outgoing mail flow

  • Accept emails from authenticated users only before sending out
  • Add DKIM signature to outgoing emails
Outgoing Mail Overview