Enabling multi DC redundancy is really easy though. The other providers you mentioned may have it by default, but they’re also a lot more expensive.

I love that they let me pick my own redundancy strategy, without forcing me to pay for theirs

ENS stands for Ethereum Name Service

I’m personally using Docker MailServer. It’s been working great for over a year now, but mailu seems to have some interesting features (I’m especially interested in the admin panel)

You’re probably behind a CGNAT, check out the other comments

Glad I could help :)

Your ISP might make you go through another layer of NAT. Can you find the WAN IP address of your router and compare it to your public IP address from a website such as ipinfo.io ?

If they do not match, you’re probably out of luck and will need to forward your port from an actually public IP in order to achieve what you want

More details : CGNAT (Carrier Grade Network Address Translation) is basically a second router between your router and the public internet. This second router is configured in the same way as your personal one, the main difference being that your ISP fully manages it. From the viewpoint of this second router, your WAN IP is a private IP, and you share one actual public IP with several other customers (the same way all devices on you LAN share one single WAN IP)

Performing port forwarding from the public internet to your LAN, when behind a CGNAT, would require you to be able to configure a forwarding rule in the ISP’s NAT, which you usually cannot do.