简单的内部 HTTP GET 请求因 SocketException 而失败：现有连接被远程主机强行关闭

Question

我有一个简单的健康检查系统，它向内部 URL 发送一个简单的 HTTP GET 请求，这是一个需要身份验证的 MVC 网络应用程序。例如，如果您向 https://{{IPAddress}}/MyMvcApp 发送获取请求，应用会将您重定向到 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);
    }
}

我的服务器场中有两台服务器。这段代码在其中一台服务器上运行时，运行正常，但是另一台服务器出现了这个问题：

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 host at 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，发现没有明显差异。
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。
已验证两者都安装了 .NET v4.0.30319。

我对此思考得越多，就越得出这样的结论：F5 负载平衡器拒绝来自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平衡器可能存在 firewall/misconfiguration 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;
        }

就这么叫吧CheckPageExists("https://www.google.com")

引用using System.Net;

Answer 2

这原来是一个 DNS 问题。文件中的某些服务器主机未包含在负载均衡器的主机文件中。终于修好了！

简单的内部 HTTP GET 请求因 SocketException 而失败：现有连接被远程主机强行关闭

Simple internal HTTP GET request failing due to SocketException: An existing connection was forcibly closed by the remote host

c#

load-balancing

tls1.2

f5