我在模拟请求[POST]一个网站的时候，一直连接不上去，总是提示我”操作超时“

  HttpWebRequest httpWebRequest = null;

            HttpWebResponse httpWebResponse = null;

            try

            {

                byte[] byteRequest = Encoding.Default.GetBytes(postData);//格式化POST数据



                httpWebRequest = (HttpWebRequest)HttpWebRequest.Create(url);//发送请求

               // httpWebRequest.CookieContainer = cookieContainer;//填充COOKIE

                //httpWebRequest.ContentType = "application/x-www-form-urlencoded";

                //httpWebRequest.ServicePoint.ConnectionLimit = maxTry;

               ;

                //httpWebRequest.Headers.Add("Accept-Language", "ko,zh-cn;q=0.5");

                //httpWebRequest.Headers.Add("Accept-Encoding", "gzip, deflate");



               // httpWebRequest.Referer = "";



                //httpWebRequest.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";

                //httpWebRequest.UserAgent = "Mozilla/5.0 (Windows NT 6.1; rv:20.0) Gecko/20100101 Firefox/20.0";

                httpWebRequest.Method = isPost ? "POST" : "GET";//那种请求？

                httpWebRequest.ContentLength = byteRequest.Length;//获取数据包大小



                Stream stream = httpWebRequest.GetRequestStream();//获取流对象

                stream.Write(byteRequest, 0, byteRequest.Length);

                stream.Close();



                httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();

                //定义数据响应信息

                Stream responseStream = httpWebResponse.GetResponseStream();//获取服务端回发达留信息



                StreamReader streamReader = new StreamReader(responseStream, encoding);