Getting users PublicIP w/Docker

[Dragonashes]

Using Docker-Compose, i am trying to show visiting users PublicIP, i am not sure what i am doing wrong. So i have managed to scrape the following together:

appsettings.json

"ServerRoute": {
    "ClusterId": "DotnetGetIP",
    "Match": {
      "Path": "/api/ip"
    },
    "Transforms": [
      {
        "ResponseHeader": "X-Forwarded-For",
        "Append": true
      }
    ]
}

controller:

[HttpGet]
public ActionResult<string> Get() {
  string Protocol = Request.Protocol;
  string HostHeader = Request.Host.ToString();
  string XForwardedFor = Request.Headers["X-Forwarded-For"].ToString().Split(',')[0] ?? "unknown";
  string RemoteIP = HttpContext.Connection.RemoteIpAddress.ToString() ?? "Unknown";
  string LocalIP = HttpContext.Connection.LocalIpAddress.ToString() ?? "Unknown";

  return Ok(new {
    RenderProtocol = Protocol,
    RenderHostHeader = HostHeader,
    RenderXForwardedFor = XForwardedFor,
    RenderRemoteIP = RemoteIP,
    RenderLocalIP = LocalIP
  });
}

Produces

{
  "renderProtocol": "HTTP/1.1",
  "renderHostHeader": "www.example.com", // privacy
  "renderXForwardedFor": "::ffff:172.20.0.1",
  "renderRemoteIP": "::ffff:172.20.0.3",
  "renderLocalIP": "::ffff:172.20.0.4"
}

So 172.18.0.1 is Docker Gateway, 172.18.0.3 is YarpProxy, 172.18.0.4 is API. I suspect the issue i have is that X-Forwarded-For is not being set up correctly, so i try to log:

program.cs

app.UseForwardedHeaders(new ForwardedHeadersOptions {
  ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto,
  ForwardLimit = null
});

app.Use(async (context, next) => {
  context.Request.Headers.TryGetValue("X-Forwarded-For", out var xForwardedFor);
  context.Request.Headers.TryGetValue("X-Forwarded-Proto", out var xForwardedProto);
  var RemoteIP = context.Connection.RemoteIpAddress?.ToString();
  var LocalIP = context.Connection.LocalIpAddress?.ToString();

  Console.WriteLine($"X-Forwarded-For: {xForwardedFor}");
  Console.WriteLine($"X-Forwarded-Proto: {xForwardedProto}");
  Console.WriteLine($"Remote IP Address: {RemoteIP}");
  Console.WriteLine($"Local IP Address: {LocalIP}");

  await next.Invoke();
});

produces

  2024-05-19 21:57:38 X-Forwarded-For:
  2024-05-19 21:57:38 X-Forwarded-Proto:
  2024-05-19 21:57:38 Remote IP Address: ::ffff:172.18.0.1
  2024-05-19 21:57:38 Local IP Address: ::ffff:172.18.0.4

Help is welcome :D

[Dragonashes]

docker/roadmap#157 referenced by Karg from Orleans discord explains it, Linux supports "host" network which looks outside Container network, unlike Windows/WSL.