UWP StreamSocket未接收TLS Alert（21）数据

Question

I'm trying to write an UWP app that communicates with a server using MQTT over HTTPS. I use StreamSocket to send the whole MQTT packet over the wire but I couldn't get any response from server. If I attempt to resend the packet, the server would terminate the connection. Using Wireshark, I can see that the server responded with a message Content-Type: Alert (21) with 26 bytes of data in it but I couldn't read it through StreamSocket.InputStream

var streamSocket = new StreamSocket();
Buffer packet;

// Building Mqtt packet.

await streamSocket.ConnectAsync(new HostName("server.com"), "443", SocketProtectionLevel.Tls12);
await streamSocket.OutputStream.WriteAsync(packet);

await Task.Delay(2000);  // Give the server some time to respond
var inputBytes = new byte[2048];
var completion = await streamSocket.InputStream.ReadAsync(inputBytes.AsBuffer(),(uint) inputBytes.Length, InputStreamOptions.Partial);

// inputBytes still empty

I want to be able to read the bytes server responded. I think there is a way to access these bytes but I could not find it anywhere.

Update: Added Wireshark result

Wireshark result

Answer 1

It seems that the problem is related with the HTTPS. Have you tried to use the UpgradeToSslAsync method, if your SSL/TLS connection is desired after sending and receiving some initial data, please use the UpgradeToSslAsync method to upgrade the connection to use SSL as following:

await streamSocket.ConnectAsync(new HostName("server.com"), "443", Windows.Networking.Sockets.SocketProtectionLevel.PlainSocket);
await streamSocket.UpgradeToSslAsync(Windows.Networking.Sockets.SocketProtectionLevel.Tls12, hostName);

Thanks,

Amy Peng