Relay all incoming email to an external provider.
My home lab has several Proxmox and other servers which sometimes want to mail me about important things. While I used to run my own SMTP server and handle this for my whole domain, the spam is just too much to filter out well, and I decided to move to a hosted SMTP provider.
Unfortunately, this makes email somewhat harder to handle for all these one-off services, and I didn't want to spread my SMTP credentials all over.
This Docker container allows me to set it up somewhere in my environment, and point all these internal SMTP-sending services to one place, which can then properly deliver to my inbox.
As credentials are used (if set), it can mail to anywhere, not just to me of course.
The container listens on port 2500, in hopes that someday I won't need to run priviledged containers. I run this in my home Kubernetes cluster. A sample statefulset is provided which also provides durable queue storage to handle container restarts without losing pending outgoing email.