static void Main(string[] args)
        {                        
               int port = 6000;
                string IP = "127.0.0.1";
                IPAddress ip = IPAddress.Parse(IP);
                IPEndPoint IPEnd = new IPEndPoint(ip, port);
                Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);//创建一个Socket类
                socket.Bind(IPEnd);//绑定2000端口
                socket.Listen(0);//开始监听
                Console.WriteLine("Wait for connect");
               
                while (true)
                {
                    Socket client = socket.Accept();//为新建连接创建新的Socket。
                    Console.WriteLine("Get a connect");
                    try{
                       
                        string str = "";
                        byte[] myBytes = new byte[1024];
                        int bytes;
                        bytes = client.Receive(myBytes, myBytes.Length, 0);//从客户端接受信息
                        str += Encoding.ASCII.GetString(myBytes, 0, bytes);
                        Console.WriteLine("Server Get Message:{0}", str);//把客户端传来的信息显示出来
                    }
                    catch (ArgumentNullException e)
                    {
                        Console.WriteLine("ArgumentNullException: {0}", e);
                        client.Close();
                        socket.Close();
                        break;
                    }
                    catch (SocketException e)
                    {
                        Console.WriteLine("SocketException: {0}", e);
                        client.Close();
                        socket.Close();
                        break;
                    }
                }                                
             Console.ReadLine();
        }

端口号你现在监听的是2000，还有一点，服务器端的IP地址不要使用127.0.0.1……

注释中端口号2000我忘了改,实际中服务器和客户端都是6000
至于ip:127.0.0.1,先用着再说.

报异常:

未处理
  Message="由于目标计算机主动拒绝，未能建立连接"
  ErrorCode=10061
  NativeErrorCode=10061
  StackTrace:
    位于 ()
    位于 ()
    位于 ()
    位于 ()
    位于 ()
    位于 ()