Self Host Intranet Email

Hi all, I am in the process of setting up authentik and had the thought of setting up an intranet email for it.

The idea is that I could set up a very simple email server and client that would only work on my home network to manage email notifications, passwords, etc from all my self hosted applications (proxmox, gitea, etc). It wouldn’t need to communicate with the outside world, only users of my intranet.

Have you done something like this? Any particular tools or advice?

I know about other options like the proton SMTP bridge but this seemed more fun!