SocketException (0x274c) while accessing service with HttpClient

问题

I have a httpClient code piece in this piece of code I requested (PostAsync) 3 times to the service like;

private async Task<Data> SendRequestToTheService(string searchTerm)
{
    using (var client = new HttpClient())
    {
        client.BaseAddress = new Uri(baseUrl);

        Response response = new Response();

        await Step1(param1, client);

        await Step2(param1, param2, client);

        response = await Step3(param, client);
        return response;
    }
}

As you can see inside of the steps I send a request(postAsync) to the same service.

In my local everything is run clean. I got response successfully.

But when I deploy my codes to the server It works few times clean then return bellowing server error.

A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond xxx.xx.xx.xxx:443

StackTrace

[SocketException (0x274c): A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond xxx.xx.xx.xxx:443]
System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult) +8439919 System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Exception& exception) +315

[WebException: Unable to connect to the remote server]
System.Net.HttpWebRequest.EndGetRequestStream(IAsyncResult asyncResult, TransportContext& context) +322
System.Net.Http.HttpClientHandler.GetRequestStreamCallback(IAsyncResult ar) +137

[HttpRequestException: An error occurred while sending the request.]
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +60 AAA.XXXX.Mvc.Controllers.d__14.MoveNext() in C:\Projects\AAA.XXXX\src\AAA.XXXX.Mvc\Controllers\SearchController.cs:276 System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +60
AAA.XXXX.Mvc.Controllers.d__11.MoveNext() in C:\Projects\AAA.XXXX\src\AAA.XXXX.Mvc\Controllers\SearchController.cs:192 System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task

task) +60 AAA.XXXX.Mvc.Controllers.d__6.MoveNext() in C:\Projects\AAA.XXXX\src\AAA.XXXX.Mvc\Controllers\SearchController.cs:87 System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +60
System.Web.Mvc.Async.TaskAsyncActionDescriptor.EndExecute(IAsyncResult asyncResult) +92
System.Web.Mvc.Async.<>c__DisplayClass37.b__36(IAsyncResult asyncResult) +22
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +42
System.Web.Mvc.Async.AsyncInvocationWithFilters.b__3d() +72 System.Web.Mvc.Async.<>c__DisplayClass46.b__3f() +385 System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) +42
System.Web.Mvc.Async.<>c__DisplayClass2b.b__1c() +38 System.Web.Mvc.Async.<>c__DisplayClass21.b__1e(IAsyncResult asyncResult) +185
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +38
System.Web.Mvc.Controller.b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +29
System.Web.Mvc.Async.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult) +65
System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +52 System.Web.Mvc.Async.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult) +36 System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +38
System.Web.Mvc.MvcHandler.b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +43
System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +65
System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +38 System.Web.CallHandlerExecutionStep.InvokeEndHandler(IAsyncResult ar) +212 System.Web.CallHandlerExecutionStep.OnAsyncHandlerCompletion(IAsyncResult ar) +166

I checked many topics about socket error (0x274c) but I didn't find any useful solution for me. Probably on my server has a network related error but I didn't solve it.

回答1:

I solved the problem. The network guy added a load balancer to the server and if the application uses different pool IP's which is not whitelisted in service so we got this exception. Thanks for comments, time and helps.

来源：https://stackoverflow.com/questions/49858830/socketexception-0x274c-while-accessing-service-with-httpclient