C＃客户端Python服务器：连接被拒绝

Question

I'm working on a basic socket communication between C# (client) and Python (server), and I don't understand the reason why I've this error from the client:

[ERROR] FATAL UNHANDLED EXCEPTION: System.Net.Sockets.SocketException: Connection refused at System.Net.Sockets.Socket.Connect (System.Net.EndPoint remoteEP) [0x00159] in /private/tmp/monobuild/build/BUILD/mono-2.10.9/mcs/class/System/System.Net.Sockets/Socket_2_1.cs:1262 at System.Net.Sockets.TcpClient.Connect (System.Net.IPEndPoint remote_end_point) [0x00000] in /private/tmp/monobuild/build/BUILD/mono-2.10.9/mcs/class/System/System.Net.Sockets/TcpClient.cs:284 at System.Net.Sockets.TcpClient.Connect (System.Net.IPAddress[] ipAddresses, Int32 port) [0x000b3] in /private/tmp/monobuild/build/BUILD/mono-2.10.9/mcs/class/System/System.Net.Sockets/TcpClient.cs:355

My programs are really short and easy so I suppose it's a noob question, but I just don't get it. All I want is a Client sending a message to the server which will print it on the console.

Here is the C# client (the error comes from :socket.Connect("localhost",9999);)

using System;
using System.Net.Sockets;

namespace MyClient
 {
class Client_Socket{
    public void Publish(){
TcpClient socket = new TcpClient();
socket.Connect("localhost",9999);
NetworkStream network = socket.GetStream();
System.IO.StreamWriter streamWriter= new System.IO.StreamWriter(network); 
streamWriter.WriteLine("MESSAGER HARGONIEN");
streamWriter.Flush();   
network.Close();
   }

}
}

And the Python Server:

from socket import *

if __name__ == "__main__":
    while(1):
        PySocket = socket (AF_INET,SOCK_DGRAM)
        PySocket.bind (('localhost',9999))
        Donnee, Client = PySocket.recvfrom (1024)
        print(Donnee)

Thx for your help.

Answer 1

You've got two problems. The first is that you're binding to localhost . You probably want to bind to 0.0.0.0 if you want other computers to be able to connect:

PySocket.bind (('0.0.0.0',9999))

The other problem is you're serving with UDP and trying to connect with TCP. If you want to use UDP, you could use UdpClient rather than TcpClient . If you want to use TCP, you'll have to use SOCK_STREAM rather than SOCK_DGRAM and use listen , accept , and recv rather than recvfrom .