Using TCP outside the LAN - c#

I'm using the the examples provided by Microsoft to learn how to use TCP servers in C#. For TCPListener I use this http://msdn.microsoft.com/en-us/library/system.net.sockets.tcplistener.aspx , and for TCPCLient I use this http://msdn.microsoft.com/en-us/library/system.net.sockets.tcpclient.aspx (the examples are at the bottom of the page).
Until now I've managed to connect and send messages to other PCs connected to the same router. What I want now is to connect it to a PC outside my LAN network. How can I do that ?
I should also mention that this is the way that I use to connect PCs in LAN :
on ther server side:
public string LocalIPAddress()
{
IPHostEntry host;
string localIP = "";
host = Dns.GetHostEntry(Dns.GetHostName());
foreach (IPAddress ip in host.AddressList)
{
if (ip.AddressFamily == AddressFamily.InterNetwork)
{
localIP = ip.ToString();
break;
}
}
return localIP;
}
private void Form1_Load(object sender, EventArgs e)
{
TcpListener server = null;
try
{
// Set the TcpListener on port 13000.
Int32 port = 13000;
String localAddrString = LocalIPAddress();
Console.WriteLine(localAddrString);
IPAddress localAddr = IPAddress.Parse(localAddrString);
// TcpListener server = new TcpListener(port);
server = new TcpListener(localAddr, port);
// Start listening for client requests.
server.Start();
}
}
on the client side:
Int32 port = 13000;
String server = "192.168.X.X"; // here I manually introduce the IP provided by the server in the console
TcpClient client = new TcpClient(server, port);

I wish I could use a simple comment to give you this information but I cannot due to me only recently joining SO. You should ensure you have port forwarded (http://portforward.com/ will help you port forward), if you don't know how to you could use this easy-to-use port checker: http://www.yougetsignal.com/tools/open-ports/.

Related

Public TCP server with C# hosted on my computer

I'm trying to run a game TCP/UDP server on my computer. It's working fine within the local network, but when I'm trying to run the server with my public IP, it just doesn't work. I've tried to disable the firewall in my router, set port forwarding for port 17000 and added a firewall rule to my computer. I've also bound IP to my computer.
I've checked client calls with Wireshark and I found out that the client (Unity game) is sending data to my IP, but it's giving TCP Retransmission error for every TCP packet that it is trying to send.
There is some of the code from server and client.
Server IP is set to 192.168.0.*:17000
And the client is connecting to my IP with port 17000
SERVER:
public static void Start(byte _maxPlayers)
{
MaxPlayers = _maxPlayers;
Port = 17000;
Console.WriteLine("Starting server..");
InitializeServerData();
tcpListener = new TcpListener(GetLocalIPAddress(), Port);
tcpListener.Start();
tcpListener.BeginAcceptTcpClient(new AsyncCallback(TCPConnectCallback), null);
udpListener = new UdpClient(Port, GetLocalIPAddress().AddressFamily);
udpListener.BeginReceive(UDPReceiveCallback, null);
Console.WriteLine($"Server started on {tcpListener.LocalEndpoint}.");
}
CLIENT:
public void Connect()
{
socket = new TcpClient
{
ReceiveBufferSize = dataBufferSize,
SendBufferSize = dataBufferSize
};
receiveBuffer = new byte[dataBufferSize];
socket.BeginConnect(instance.ip, instance.port, ConnectCallback, socket);
}
private void ConnectCallback(IAsyncResult _result)
{
socket.EndConnect(_result);
if (!socket.Connected)
return;
stream = socket.GetStream();
receivedData = new Packet();
stream.BeginRead(receiveBuffer, 0, dataBufferSize, ReceiveCallback, null);
}
So I've found out, that I have two-router set up, and because I was forwarding port 17000 just on one router, it didn't work.

SocketException when attempting to connect with TcpClient

When I try to create a new TcpClient I am getting a SocketException, here is my code:
public void TcpOpenConnection()
{
// The next line is where the exception is occurring.
tcpClient = new TcpClient(ipAddress, port);
connected = true;
}
I have checked to make sure the port is open with netstat -a in cmd, and I even made another function to check if the port is open:
public static bool PortCheck(int port)
{
bool portOpen = false;
IPGlobalProperties ipGlobalProperties = IPGlobalProperties.GetIPGlobalProperties();
TcpConnectionInformation[] tcpConnInfo = ipGlobalProperties.GetActiveTcpConnections();
foreach (var tcpConn in tcpConnInfo)
{
if (tcpConn.LocalEndPoint.Port == port)
{
portOpen = true;
break;
}
}
return portOpen;
}
which returns true. The exception that I am getting is a SocketException and it is saying the machine I am trying to connect to is actively refusing the connection. What could be the issue here? I have also tried other ports, with no luck.
If you need more info please ask, and I will gladly supply more.
The exception that I am getting is a SocketException and it is saying the machine I am trying to connect to is actively refusing the connection.
This is likely an indication that the target host isn't listening on the port which could be caused by a number of reasons:
The router of the server's network is not correctly port-forwarded
The router's firewall / server's firewall is blocking the connections
The server and the client are not using the same port
The server is misconfigured
The list goes on... but essentially, this error means that the server isn't allowing the connection.
If the port is open and you try to connect to. You get SocketException because there is nothing for get the client connection.
So you need to host a Tcplistner on this port.
static void StartServer()
{
int port = 150;
TcpListener listner = new TcpListener(IPAddress.Any, port);
listner.Start();
// This line waits the client connection.
TcpClient remote_client = listner.AcceptTcpClient();
// do something with remote_client.
}
And you can connect to.
static void StartClient()
{
int port = 150;
IPAddress ip = IPAddress.Parse("127.0.0.1");
TcpClient client = new TcpClient();
client.Connect(ip, port);
// Do something with client.
}

Other computers can't connect my program

I'm building a C# chat program, yet I'm facing a problem with outside connection.
When the same computer connects both as server and as client, there seems to be no problem, yet when I try to host the connection on one computer, the other can't connect as a client.
here's the relevant code:
class Server:
public void Connect(string ipAddr, string port)
{
server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPEndPoint ipLocal = new IPEndPoint(IPAddress.Any, Convert.ToInt32(port));
server.Bind(ipLocal);//bind to the local IP Address...
server.Listen(5);//start listening...
// create the call back for any client connections...
server.BeginAccept(new AsyncCallback(OnClientConnect), null);
}
public void Disconnect()
{
server.Close();
server = null;
tempSocket = null;
}
public void OnClientConnect(IAsyncResult asyn)
{
try
{
if (server != null)
{
tempSocket = server.EndAccept(asyn);
WaitForData(tempSocket);
server.BeginAccept(new AsyncCallback(OnClientConnect), null);
}
}
catch (ObjectDisposedException)
{
Debugger.Log(0, "1", "OnClientConnect: Socket has been closed.");
}
catch (Exception e)
{
MessageBox.Show(e.Message, "OnClientConnect Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
Client class:
public void Connect(string ipAddr, string port)
{
client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPEndPoint ipe = new IPEndPoint(IPAddress.Parse(ipAddr), Convert.ToInt32(port));
client.Connect(ipe);
clientListener = new Thread(OnDataReceived);
isEndClientListener = false;
clientListener.Start();
}
I have no idea what's wrong here. Hope you can tell me what's wrong.
Your issue is probably not code related. In order for other people outside your network to conenect to you, you need to port forward the port that you are connecting through on your router. You can find many tutorials here. You may also check to see if your connection is open through this tool.
From Wikipedia:
Port forwarding allows remote computers (for example, computers on the Internet) to connect to a specific computer or service within a private local-area network (LAN).
You must allow connections through your router to be able to connect to your chat server.
You need to give your computer a public IP address (maybe your router has this option) or implement port forwarding on your router.
A Public IP address would be the one of your router. Check out this site to find out your public IP whatismyipaddress.com. Your router can or cannot support the option to give its public IP address to your computer, however, your router should be able to do port forwarding. (Forwarding the data from a specific port to a specific computer, so when someone connects to your public IP. For example 93.93.93.93:3333 will be forwarded to your PC.)

TCP Debug Error C#

public Server([Optional, DefaultParameterValue(0x6c1)] int port, [Optional, DefaultParameterValue("127.0.0.1")] string ip)
{
this.IP = IPAddress.Parse(ip);
this.Port = port;
this.listenerConnection = new TcpListener(this.IP, this.Port);
this.listenerConnection.Start();
this.listenerThread = new Thread(new ThreadStart(this.listen));
this.listenerThread.Start();
}
is the code I have, it runs fine but when I debug it, I get the message:
Specified argument was out of the range of valid values. Parameter name: port
Can anyone help?
Well, then port is out of the range of valid values, which is between IPEndPoint.MinPort and IPEndPoint.MaxPort.
Have you tried using the IPAddress of your machine? You can use the following code to obtain the IPAddress of the machine you are running the application on:
IPHostEntry host = Dns.GetHostEntry(Dns.GetHostName());
IPAddress localIpAddress = null;
forach(IPAddress address in host.AddressList)
{
if(address.AddressFamily == AddressFamily.InterNetwork)
{
localIpAddress = address;
}
}
TcpListener listener = new TcpListener(localIpAddress, port);
listener.Start();
Additionally, you may want to consider using a default port > 5000. As there are many ports between 0 and 5000 that are reserved or already use by services.

Unable to connect from remote machine

I have some kind of problem and I can't check this at home if its working or not.
Here is the code
using System;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using System.IO;
using System.Net.Security;
class Program
{
private static IPAddress ipAddress = IPAddress.Parse("127.0.0.1");
private static int port = 6000;
private static string data = null;
static void Main(string[] args)
{
Thread thread = new Thread(new ThreadStart(receiveThread));
thread.Start();
Console.ReadKey();
}
public static void receiveThread()
{
while (true)
{
TcpListener tcpListener = new TcpListener(ipAddress, port);
tcpListener.Start();
Console.WriteLine("Waiting for connection...");
TcpClient tcpClient = tcpListener.AcceptTcpClient();
Console.WriteLine("Connected with {0}", tcpClient.Client.RemoteEndPoint);
while (!(tcpClient.Client.Poll(20, SelectMode.SelectRead)))
{
NetworkStream networkStream = tcpClient.GetStream();
StreamReader streamReader = new StreamReader(networkStream);
data = streamReader.ReadLine();
if(data != null)
Console.WriteLine("Received message: {0}", data);
}
Console.WriteLine("Dissconnected...\n");
tcpListener.Stop();
}
}
}
I have a simple program as well to connect to this and then send a string with data. It works fine on localhost but there is a problem when I'm trying to connect with a different coputer.
I even turned off the firewall on my PC and router, as I did on my friend's laptop. Every time I have tried to connect, his computer refused connection. Maybe I'm doing something wrong?
Of course, ipAddress is a local address now since it's only working with that at the moment. Any suggestions what to do?
You need to set it to accept connections from any IP, there is an IPAddress overload function for this:
System.Net.IPAddress.Any
use it instead of 127.0.0.1 and it will fix your problem.
You're listening on 127.0.0.1 which is the loopback address which is a special address that means 'this computer'. This means that you will only accept connections that are made on the same machine as the server is running on.
You need to listen on one (or more) of the server's real ip addresses.
Your problem is that the setting an IP address explicitly when you initialize the TcpListener will only allow it to accept connections from that address. Therefore, putting in the local address of 127.0.0.1 will only accept connections originating from your PC.
The implementation you want to use is as follows:
TcpListener tcpListener = new TcpListener(IPAddress.Any, port);
This will allows connections from any IP address to connect to your program on the specified port.
I think it is your computer (the server) that refuses to connect because 127.0.0.1 is local(-only).
Try this simple overload:
TcpListener tcpListener = new TcpListener(port);

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