如何解决“现有连接被远程主机强行关闭”错误？

问：

我正在尝试使用 ASP.Net Core 6 连接服务器。当我在本地主机上运行它时，它工作正常，但是当我在服务器上发布时，出现错误。我将我的 Server 项目发布到 FileZilla。IP 地址和端口正确无误。但是，我收到此错误消息：

插座已连接。
向服务器发送了 19 个字节。
System.Net.Sockets.SocketException （10054）： 远程主机强行关闭了现有连接。 在 System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.ThrowException （SocketError 错误，CancellationToken cancellationToken） 在 System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.System.Threading.Tasks.Sources.IValueTaskSource<System.Int32>。GetResult（Int16 令牌） 在 System.Threading.Tasks.ValueTask'1.ValueTaskSourceAsTask.<>c.<.cctor>b__4_0 （对象状态） --- 从上一个位置---结束堆栈跟踪 在 System.Threading.Tasks.TaskToApm.End [TResult] （IAsyncResult asyncResult） 在 System.Net.Sockets.Socket.EndReceive （IAsyncResult asyncResult） 在 C：\Users\rozer\source\repos\Client1\Client1\Program.cs：第 129 行中的异步客户端.ReceiveCallback（IAsyncResult ar）

错误行：

int bytesRead = client.EndReceive(ar);

我明白已经建立了联系。但是我不明白为什么它被远程主机强行关闭，我得到了这个错误。是关于防火墙问题还是类似问题？我该如何解决这个问题？

这是我的客户端项目，用于检查连接：

using System.Net;
using System.Net.Sockets;
using System.Threading;
using System.Text;

// State object for receiving data from remote device.  
public class StateObject
{
    // Client socket.  
    public Socket workSocket = null;
    // Size of receive buffer.  
    public const int BufferSize = 256;
    // Receive buffer.  
    public byte[] buffer = new byte[BufferSize];
    // Received data string.  
    public StringBuilder sb = new StringBuilder();
}

public class AsynchronousClient
{
    // The port number for the remote device.  
    private const int port = 443;

    // ManualResetEvent instances signal completion.  
    private static ManualResetEvent connectDone =
        new ManualResetEvent(false);
    private static ManualResetEvent sendDone =
        new ManualResetEvent(false);
    private static ManualResetEvent receiveDone =
        new ManualResetEvent(false);

    // The response from the remote device.  
    private static String response = String.Empty;

    private static void StartClient()
    {
        // Connect to a remote device.  
        try
        {
            // Establish the remote endpoint for the socket.  
            // The name of the
            // remote device is "host.contoso.com".  
            IPHostEntry ipHostInfo = Dns.GetHostEntry("networks.net");
            IPAddress ipAddress = ipHostInfo.AddressList[0];
            IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);

            // Create a TCP/IP socket.  
            Socket client = new Socket(ipAddress.AddressFamily,
                SocketType.Stream, ProtocolType.Tcp);

            // Connect to the remote endpoint.  
            client.BeginConnect(remoteEP,
                new AsyncCallback(ConnectCallback), client);
            connectDone.WaitOne();

            // Send test data to the remote device.  
            Send(client, "deneme fkfglb <EOF>");
            sendDone.WaitOne();

            // Receive the response from the remote device.  
            Receive(client);
            receiveDone.WaitOne();

            // Write the response to the console.  
            Console.WriteLine("Response received : {0}", response);

            // Release the socket.  
            client.Shutdown(SocketShutdown.Both);
            client.Close();

        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
        }
    }

    private static void ConnectCallback(IAsyncResult ar)
    {
        try
        {
            // Retrieve the socket from the state object.  
            Socket client = (Socket)ar.AsyncState;

            // Complete the connection.  
            client.EndConnect(ar);

            Console.WriteLine("Socket connected to {0}",
                client.RemoteEndPoint.ToString());

            // Signal that the connection has been made.  
            connectDone.Set();
        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
        }
    }

    private static void Receive(Socket client)
    {
        try
        {
            // Create the state object.  
            StateObject state = new StateObject();
            state.workSocket = client;

            // Begin receiving the data from the remote device.  
            client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
                new AsyncCallback(ReceiveCallback), state);
        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
        }
    }

    private static void ReceiveCallback(IAsyncResult ar)
    {
        try
        {
            // Retrieve the state object and the client socket
            // from the asynchronous state object.  
            StateObject state = (StateObject)ar.AsyncState;
            Socket client = state.workSocket;

            // Read data from the remote device.  
            int bytesRead = client.EndReceive(ar);

            if (bytesRead > 0)
            {
                // There might be more data, so store the data received so far.  
                state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, bytesRead));

                // Get the rest of the data.  
                client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
                    new AsyncCallback(ReceiveCallback), state);
            }
            else
            {
                // All the data has arrived; put it in response.  
                if (state.sb.Length > 1)
                {
                    response = state.sb.ToString();
                }
                // Signal that all bytes have been received.  
                receiveDone.Set();
            }
        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
        }
    }

    private static void Send(Socket client, String data)
    {
        // Convert the string data to byte data using ASCII encoding.  
        byte[] byteData = Encoding.ASCII.GetBytes(data);

        // Begin sending the data to the remote device.  
        client.BeginSend(byteData, 0, byteData.Length, 0,
            new AsyncCallback(SendCallback), client);
    }

    private static void SendCallback(IAsyncResult ar)
    {
        try
        {
            // Retrieve the socket from the state object.  
            Socket client = (Socket)ar.AsyncState;

            // Complete sending the data to the remote device.  
            int bytesSent = client.EndSend(ar);
            Console.WriteLine("Sent {0} bytes to server.", bytesSent);

            // Signal that all bytes have been sent.  
            sendDone.Set();
        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
        }
    }

    public static int Main(String[] args)
    {
        StartClient();
        return 0;
    }
} ```