由于意外的数据包格式，WebRequest握手失败

Question

我有许多ASP.NET网站和使用相同代码“登录”到第三方网站的web服务。这包括基本上使用WebRequest通过我的凭证对网站的登录页面执行HTTP POST，将产生的Cookie存储在CookieContainer中，并在任何以下WebRequest中使用该CookieContainer将我的网站授权给第三方网站上的页面。

的代码基本如下：

public LoginResults Login() 
    { 
     // Create the webrequest 
     var request = CreateInitialWebRequest(LOGIN_URL); 
     request.AllowAutoRedirect = false; 

     // Set the cookiecontainer, which will be filled with the authentication cookies 
     this.cookieContainer = new CookieContainer(); 
     request.CookieContainer = this.cookieContainer; 

     // Set the username and pw in a HTTP POST call 
     SetPostContent(request, string.Format(LOGIN_PARAMETERS, this.Username, this.Password)); 

     // Read the response 
     using (var httpWebResponse = (HttpWebResponse)request.GetResponse()) 
     { 
      using (var responseStream = httpWebResponse.GetResponseStream()) 
      { 
       // Omitted: 
       // read response and determine if login was successful 
      } 
     } 
    } 

    private HttpWebRequest CreateInitialWebRequest(string uri) 
    { 
     var request = (HttpWebRequest)WebRequest.Create(uri); 
     ServicePointManager.ServerCertificateValidationCallback = delegate { return true; }; 
     return request; 
    } 

    private HttpWebRequest CreateWebRequest(string uri) 
    { 
     var request = this.CreateInitialWebRequest(uri); 
     request.CookieContainer = cookieContainer; 
     request.Accept = "image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-ms-application, application/vnd.ms-xpsdocument, application/xaml+xml, application/x-ms-xbap, application/x-shockwave-flash, */*"; 
     request.UserAgent = "User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.0.04506; .NET CLR 3.5.21022)"; 
     request.Method = "GET"; 
     request.Timeout = 10000; // 10 sec 
     return request; 
    } 

    private static void SetPostContent(HttpWebRequest req, string postData) 
    { 
     req.Method = "POST"; 
     byte[] bytes = new ASCIIEncoding().GetBytes(postData); 
     req.ContentType = "application/x-www-form-urlencoded"; 
     req.ContentLength = (long)bytes.Length; 
     ((WebRequest)req).GetRequestStream().Write(bytes, 0, bytes.Length); 
     ((WebRequest)req).GetRequestStream().Close(); 
    } 

该代码已经工作了很长的时间（几个月，过了半年）。自从这个周末以来，它已经开始失败（我估计有90％的时间，但不是100％的时间）。我一直看到的错误是：System.Net.WebException：底层连接已关闭：发送时发生意外错误。 ---> System.IO.IOException：由于意外的数据包格式，握手失败。 的堆栈跟踪如下：

System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a send. ---> System.IO.IOException: The handshake failed due to an unexpected packet format. 
at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest) 
at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest) 
at System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest) 
at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest) 
at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest) 
at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult) 
at System.Net.TlsStream.CallProcessAuthentication(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.Net.TlsStream.ProcessAuthentication(LazyAsyncResult result) 
at System.Net.TlsStream.Write(Byte[] buffer, Int32 offset, Int32 size) 
at System.Net.PooledStream.Write(Byte[] buffer, Int32 offset, Int32 size) 
at System.Net.ConnectStream.WriteHeaders(Boolean async) 
--- End of inner exception stack trace --- 
at System.Net.HttpWebRequest.GetRequestStream(TransportContext& context) 
at System.Net.HttpWebRequest.GetRequestStream() 
at iRacingForumService.HttpPost.SetPostContent(HttpWebRequest req, String postData) 
at iRacingForumService.HttpPost.Login() 

当我谷歌这个错误我一直看到的唯一的解决办法是禁用的WebRequest和/或设置ProtocolVersion到HttpVersion10的KeepAlive属性。我尝试了两种（每种组合都可能），没有任何帮助。

错误并不总是出现，但是当它确实出现时，我可以继续尝试所有我喜欢的，我会不断地收到错误。如果我离开它几分钟，然后再试一次，我有可能会发挥作用（一旦它结束，它将继续工作一段时间）。

奇怪的是，我没有改变我的任何事情;这段代码已经运行了好几个月没有问题。第三方网站完全有可能改变某些事情，或者我的虚拟主机提供商改变了一些东西。但为了万一我可以采取一些措施来解决这个问题，我想问我是否做错了什么。

我可以联系第三方网站（可能不会得到回复）或我的网站主持人，但我需要更好地了解到底发生了什么问题，因为把这个错误告诉他们可能无济于事。

那么，有什么我可以做的，还是有一个很好的理由，为什么我突然在我的所有网站（他们都连接到同一个第三方网站）看到这个错误？

感谢

Answer 1

由于这种情况间歇性地，您可能需要与服务器管理员联系，了解怎么回事。由于加载，配置错误或其他网络问题，服务器可能会拒绝或关闭连接。