How do I change the IP/Port of the SMTP server?

[Infinoid]

Hi,

I've been trying to use papercut in a development environment that runs in an ipv6-only kubernetes cluster, and had a few problems. It seems like the configuration values for SMTP server IP and Port are ignored?

My goals are to listen on address :: (IPv6Any) and port 8025. However, whatever I try, the container logs always say:

[timestamp] Starting Smtp Server on 0.0.0.0:25...

I'm unable to affect the above, neither address nor port, no matter what I do. I was able to change the HTTP addr/port easily by adding a Urls field to appsettings.json, so this seems to only be a problem for SMTP.

I've tried:

appsettings.json:

{
  "SmtpServer": {
    "Port": 8025
  }
}

appsettings.Production.json:

{
  "SmtpServer": {
    "Port": 8025
  }
}

Papercut.SMTP.Service.Settings.json:

{
  "Port": "8025"
}

Papercut.Service.Settings.json:

{
  "Port": "8025"
}

environment vars:

• PORT=8025
• SMTP_PORT=8025

The only way I could find to get it working is to run a reverse proxy process to forward incoming ipv6 connections to ipv4, and run the process as root within its container (because binding to ports < 1024 requires special credentials).

So, I want to ask: what's the right way to configure the SMTP service's ip/port when running the papercut-smtp docker image? And would it be possible to provide an example of that?

Thanks!