为什么我可以将数据从TCP客户端发送到服务器，但反之亦然？

Question

我在C＃中编写了一个异步TCP服务器客户端。当我在一台计算机上测试它们时，两个程序都成功运行（服务器和客户端在同一台机器上同时运行）。但是，当在两台不同的计算机上进行测试时，建立了服务器 - 客户端连接，客户端能够将数据发送到服务器，但服务器似乎没有向其客户端发送任何内容。

通过使用TCPView，我知道服务器和客户端都按预期接收/发送数据。我以为是阻止它们的防火墙，我已禁用它并且没用。我的代码出了什么问题？

服务器：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net.Sockets;
using System.Net;

// Server code
namespace ChatConsole
{
    class Program
    {
        static Socket serverSocket, clientSocket;
        static byte[] buffer;
        const int defaultBufferSize = 1024;

        static void Main(string[] args)
        {
            try
            {
                Console.WriteLine("This is server.");

                // Create a new server socket.
                serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

                // Create IP End Point.
                IPEndPoint ep = new IPEndPoint(IPAddress.Any, 1001);

                // Bind endpoint to socket.
                serverSocket.Bind(ep);

                // Start listening for incoming client.
                serverSocket.Listen(4);

                // Execute callback method when client request connection.
                serverSocket.BeginAccept(new AsyncCallback(AcceptCallback), null);

                while (true) { }
            }
            catch(Exception ex)
            {
                Console.WriteLine("from Main(): " + ex.Message);
            }

        }

        private static void AcceptCallback(IAsyncResult ar)
        {
            try
            {
                // Store client socket handle.
                clientSocket = serverSocket.EndAccept(ar);
                Console.WriteLine("Client {0} joined.", clientSocket.RemoteEndPoint);

                // Welcome the client when connection established.
                buffer = Encoding.ASCII.GetBytes("Hello from server!");
                clientSocket.BeginSend(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(SendCallback), null);

                // Begin receiving data from  connected client.
                buffer = new byte[1024];
                clientSocket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveCallback), null);
            }
            catch (Exception ex)
            {
                Console.WriteLine("from AcceptCallback(): " + ex.Message);
            }

        }

        private static void SendCallback(IAsyncResult ar)
        {
            // Terminate current send session.
            clientSocket.EndSend(ar);
            Console.WriteLine("Replied.");
        }

        private static void ReceiveCallback(IAsyncResult ar)
        {
            try
            {
                // Store the length of received data.
                int received = clientSocket.EndReceive(ar);
                if (received == 0)
                    return;

                // Convert the received data to string then print in the console.
                Array.Resize<byte>(ref buffer, received);
                string text = Encoding.ASCII.GetString(buffer);
                Console.WriteLine(text);
                Array.Resize<byte>(ref buffer, defaultBufferSize);

                // Send back message from the client.
                byte[] data = Encoding.ASCII.GetBytes("from server: " + text);
                clientSocket.BeginSend(data, 0, data.Length, SocketFlags.None, new AsyncCallback(SendCallback), null);

                clientSocket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveCallback), null);
            }
            catch (Exception ex)
            {
                Console.WriteLine("from ReceiveCallback(): " + ex.Message);
            }

        }
    }
}

客户端：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net.Sockets;
using System.Net;

// Client code
namespace ChatConsoleClient
{
    class Program
    {
        static Socket clientSocket;
        static IPEndPoint ep;
        static byte[] buffer;
        const int defaultBufferSize = 1024;

        static void Main(string[] args)
        {
            try
            {
                Console.WriteLine("This is client.");

                // Create new socket for client.
                clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

                // Ask for server IP address.
                string IP = Console.ReadLine();

                // Create endpoint to be connected.
                ep = new IPEndPoint(IPAddress.Parse(IP), 1001);

                // Start connecting to the server.
                clientSocket.BeginConnect(ep, new AsyncCallback(ConnectCallback), null);
                buffer = new byte[1024];

                clientSocket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveCallback), null);

                while (true)
                {
                    string text = Console.ReadLine();
                    byte[] data = Encoding.ASCII.GetBytes(text);

                    clientSocket.BeginSend(data, 0, data.Length, SocketFlags.None, new AsyncCallback(SendCallback), null);
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine("from Main(): " + ex.Message);
            }

        }

        private static void ReceiveCallback(IAsyncResult ar)
        {
            int received = clientSocket.EndReceive(ar);
            if (received == 0)
                return;

            // Convert the received data to string then print in the console.
            Array.Resize<byte>(ref buffer, received);
            string text = Encoding.ASCII.GetString(buffer);
            Console.WriteLine(text);
            Array.Resize<byte>(ref buffer, defaultBufferSize);
            clientSocket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveCallback), null);
        }

        private static void SendCallback(IAsyncResult ar)
        {
            clientSocket.EndSend(ar);
        }

        private static void ConnectCallback(IAsyncResult ar)
        {
            clientSocket.EndConnect(ar);
        }
    }
}

Answer 1

我检查了在两个不同系统中运行的客户端和服务器，但它们都具有相同的IP系列并且可以正常工作