AWS support?

Describe the bug

Is this a bug? Of not supported? I am trying to connect to AWS IoT with client certificate over port 8883. I see some references to ALPN but that doesn’t seem a hard requirement. But I couldn’t find anyway to configure ALPN as well, so that might be related.

Which project is your bug related to?

• Client

Details

I checked that the certificates are valid by using “openssl s_client -CAfile ca.pem -cert client.pem -key client.key -connect your-endpoint.amazonaws.com:8883”. Also, I catch the certificate errors in MQTTnet so that all seems fine. But when I try a ConnectAsync, this is the error I receive: “MQTTnet.Exceptions.MqttCommunicationTimedOutException’ was thrown”.

MQTTnet.Exceptions.MqttCommunicationTimedOutException
  HResult=0x80131500
  Message=Exception of type 'MQTTnet.Exceptions.MqttCommunicationTimedOutException' was thrown.
  Source=mscorlib
  StackTrace:
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MQTTnet.PacketDispatcher.MqttPacketAwaiter`1.<WaitOneAsync>d__4.MoveNext()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MQTTnet.Client.MqttClient.<SendAndReceiveAsync>d__50`1.MoveNext()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MQTTnet.Client.MqttClient.<AuthenticateAsync>d__44.MoveNext()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
   at MQTTnet.Client.MqttClient.<ConnectAsync>d__35.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at MQTTnet.Client.MqttClient.<ConnectAsync>d__35.MoveNext()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at MyProgram.MyProg.PD() in MyProgram.vb:line 577
   at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()

[Chef904]

Hi, i am not able to connect with AWS IoT over TLS. Is there anywhere an complete code example with MQTTnet? With M2Mqtt i got an successful connectien.

[nicolasr75]

For others trying this I would like to mention two pitfalls that at first prevented me from publishing messages. Quoted from the AWS IoT docs:

AWS IoT supports MQTT quality of service (QoS) levels 0 and 1 only. AWS IoT doesn’t support publishing or subscribing with QoS level 2. When QoS level 2 is requested, the message broker doesn’t send a PUBACK or SUBACK.

The MQTT specification provides a provision for the publisher to request that the broker retain the last message sent to a topic and send it to all future topic subscribers. AWS IoT doesn’t support retained messages. If a request is made to retain messages, the connection is disconnected.

Meaning, don’t use .WithExactlyOnceQoS(), .WithRetainFlag()