c# - 由于 SocketException : An existing connection was forcibly closed by the remote host，简单的内部 HTTP GET 请求失败

Question

我有一个简单的健康检查系统，它向一个内部 URL 发送一个简单的 HTTP GET 请求，这是一个需要身份验证的 MVC Web 应用程序。例如，如果您向 https://{{IPAddress}}/MyMvcApp 发送获取请求，应用程序会将您重定向到 https://{{LB Host}}/MyMvcAppAuth .

private static void UsingHttpGetRequest(string uri, Action<HttpWebResponse> action)
{
    ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
    request.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;

    ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback
    (
        delegate { return true; }
    );

    Log("Sending the HTTP Get request...");
    using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
    {
        Log($"Got a response! Status: {response.StatusCode}");
        action(response);
    }
}

我的农场中有两台服务器。当此代码在其中一台服务器上运行时，它工作正常，但另一台服务器出现此问题:

Exception: System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a send. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote hostat System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags)at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)

我比较了服务器之间的 IIS 配置设置，没有发现显着差异。

我比较了注册表项，发现两台服务器都没有注册表项“SchUseStrongCrypto”，但两台服务器上肯定都启用了 TLS 1.2。

验证两者都安装了 .NET v4.0.30319。

我对此考虑得越多，我就越得出结论，即 F5 负载平衡器拒绝来自服务器场中其中一台服务器的请求的 302 重定向。你们有什么感想？拒绝这些请求的负载均衡器上潜在的防火墙/错误配置问题？

Answer 1

另一种方法。

       public static bool CheckPageExists(string url)
        {
            //checks only the headers to be very quick
            bool pageExists = false;
            try
            {
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
                request.Method = WebRequestMethods.Http.Head;
                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                pageExists = response.StatusCode == HttpStatusCode.OK;
            }
            catch
            {
                return false;
            }
            return pageExists;
        }

就这样称呼它 CheckPageExists("https://www.google.com")引用 using System.Net;