- The HASS_API is correct if HASS and the configurator are running on the same machine.
- You can forward whatever port you like. To keep it simple, just forward 3218 to 3218.
I assume you’re using the panel_iframe. In that case you have to configure it to point to
yourdomain:3218, where 3218 is the port you are forwarding to the configurator. Don’t forget to set up authentication. Otherwise external access to your configuration as possible for everybody.
In any case, you should also be able to directly access the configurator by browsing to
yourdomain:3218 as soon as the port forwarding is active. Essentially the panel_iframe has to point to the URL that enables you to access the configurator directly from outside.