Xamarin iOS (WebClient IPv6 Rejection)

Question

My Apple AppStore application was rejected for not supporting IPv6 networks.

Here is declaration of my server URL for WebClient. "ipv4" is IPv4 address of server. I didn't add it here to stay secure.

RemoteServerConnector.Instance.DefaultServerUrl = "http://ipv4/api.php"; 

Then I have this method to check connection:

   private class MyWebClient : WebClient {

    public int timeOut { get; set; }

    protected override WebRequest GetWebRequest(Uri address) {
        WebRequest w = base.GetWebRequest(address);
        w.Timeout = timeOut;
        return w;
    }
   }

   public bool checkInternetConnection() {
            try {
                using(MyWebClient client = new MyWebClient()) {
                    client.timeOut = ApiUrls.RemoteServerConnectorTestTimeout;
                    var removeString = "api.php";
                    var testHttp = DefaultServerUrl.EndsWith(removeString) ? DefaultServerUrl.Remove(DefaultServerUrl.Length - removeString.Length, removeString.Length) : DefaultServerUrl;            

                    using(client.OpenRead(testHttp)) {
                        return true;
                    }
                }
            } catch(WebException ex) {
                return ex.Status != WebExceptionStatus.ConnectFailure;
            } catch(Exception ex) {
                return false;
            }
        }

It always throw exception in IPv6 networks. I already tried this solution Xamarin iOS IPv6 App Store Rejection, but it doesn't work. I also tried to add IPv6 instead of IPv4 in variable DefaultServerUrl. I also tried http://ipv6/api.php and also http://[ipv6]/api.php

Can't find any solution for this type of connection (WebClient). I found only other solutions with TCP/IP protocol and I don't want to change it in my app.

I also saw Xamarin blog about IPv6, but I don't know what to do. Couldn't add link to it, because of permissions.

What should I change in my code to make it working? Thank you for your time :)

Answer 1

As I tried almost everything and it didn't work I checked settings of customers server. There was not settings for IPv6. We fixed it and now it is working with with ModernHttpClient. I switched in app from IPv4 address to hostname.

My code for ModernHttpClient.

                var handler = new NativeMessageHandler();
                using (var client = new HttpClient(handler))
                {
                    client.Timeout = TimeSpan.FromMilliseconds(ApiUrls.RemoteServerConnectorTestTimeout);
                    var removeString = "api.php";
                    var testHttp = DefaultServerUrl.EndsWith(removeString) ? DefaultServerUrl.Remove(DefaultServerUrl.Length - removeString.Length, removeString.Length) : DefaultServerUrl;

                    using (client.GetAsync(testHttp).Result)
                    {
                        return true;
                    }

                }