Mailcow setup for CasaOS

I would love to know how mailcow works and wat’s required to get it setup in my homelab, this because i need a SMTP server to send mail from some internal services to my primary M365 mail (SMTP not supported without API, which i also don’t have available trough my account).

Typically, on home networks, ISPs block port 25 to prevent spamming. This helps mitigate unauthorized email transmissions from residential connections. Additionally, using port 25 could expose your home IP address to potential security risks. For reliable email service, especially if you’re hosting your own mail server, a static IP address is often necessary to ensure your server remains consistently accessible.

You could get a server from someone like Hetzner and run it.