Develop Reference

UDP Client server works on same computer but not over lan

I have a simple application that sends continuous UDP packets from a server to a client. Everything works well if the server app and client app are on the same computer but the minute I move the client to another computer in the LAN it stops working with a message
"the requested address is not valid in its context". I really don't understand why this is happening.
Here is the server code:
public void SendData()
{
udpClient = new UdpClient();
for (int i = 0; i < 8192; i++)
{
dataBytes[i] = Convert.ToByte(Convert.ToInt16(dataValues[i]));
}
udpClient.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
try
{
udpClient.Connect(ipAddress, port);
udpClient.Send(dataBytes, dataBytes.Length);
}
catch (Exception ex)
{
}
}
On the client machine here is the code:
private void receive()
{
try
{
udpClient = new UdpClient();
udpClient.Client.ReceiveTimeout = 1000;
udpClient.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
int port = Convert.ToInt32("13064");
IPAddress ipAddress = IPAddress.Parse("192.168.1.107");
IPEndPoint localEndPoint = new IPEndPoint(ipAddress, port);
socket = new UdpClient(localEndPoint);
udpClient.Connect(ipAddress, port);
socket.BeginReceive(new AsyncCallback(ReceivedDataCallback), socket);
}
catch (Exception ex)
{
if (!socketConnected)
{
MessageBox.Show(ex.Message, Application.ProductName, MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
}
private void ReceivedDataCallback(IAsyncResult AR)
{
try
{
socketConnected = true;
clientSocket = AR.AsyncState as UdpClient;
var port = Convert.ToInt32("13064");
IPAddress ipAddress = IPAddress.Parse("192.168.1.107");
IPEndPoint source = new IPEndPoint(ipAddress, port);
nums = clientSocket.EndReceive(AR, ref source);
OutputRemoteSamples();
clientSocket.BeginReceive(new AsyncCallback(ReceivedDataCallback), clientSocket);
}
catch (Exception ex)
{
}
}
Thanks for any suggestions
Tom

Why won't my client connect to my server?

So I'm trying to make a simple chat server that sends an object, Message between them. My server creation/connection code is
IPHostEntry ipHost = Dns.GetHostEntry(Dns.GetHostName());
IPAddress ipAddr = ipHost.AddressList[0];
IPEndPoint localEndPoint = new IPEndPoint(ipAddr, port);
Socket serverSocket = new Socket(ipAddr.AddressFamily,
SocketType.Stream, ProtocolType.Tcp);
System.Console.WriteLine("Socket running on port " + port);
System.Console.WriteLine(ipHost);
serverSocket.Bind(localEndPoint);
System.Console.WriteLine("Accepting Connections");
serverSocket.Listen(10);
while (true)
{
Socket clientSocket = serverSocket.Accept();
Thread t = new Thread(() => Login.login(clientSocket));
System.Console.WriteLine("Client accepted.");
}
and my client creation/connection code is
System.Console.WriteLine("attempting to connect");
Socket clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
System.Console.WriteLine("tesinft3");
clientSocket.Connect(IPAddress.Parse(server's external IP address), port);
System.Console.WriteLine("tesinft4");
System.Console.WriteLine("Connected to Server");
When I try to connect the client to the server I get attempting to connect and testinft3 and that's it. After about 30 seconds they appear again, but they still won't connect. How can I fix this?

C# Socket works locally but not remotely

I have a C# Client and a seperate Server application. When i execute both on the same machine, im able to connect to the server. However, when i try to connect to my server remotely it always ends in a timeout. I use the port 139 and I tried running the server application on mulitple machines. I have tried it on a server that is open to the public, my private PC with my router forwarding this port to the PC, as well as laptops in the same network.
I have always checked if the machine the server is running on is listening on the port using netstat -an and made exceptions in the firewall on all of them.
The code I use on the client to connect to the server:
static IPHostEntry ipHostInfo = Dns.GetHostEntry("xxx.xxx.xxx.xxx");
static IPAddress ipAddress = ipHostInfo.AddressList[0];
static IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);
static Socket client = new Socket(ipAddress.AddressFamily,
SocketType.Stream, ProtocolType.Tcp);
static private void ConnectToServer()
{
try
{
client.BeginConnect(remoteEP,
new AsyncCallback(ConnectCallback), client);
connectDone.WaitOne();
}
catch (Exception ex)
{
Console.WriteLine("Error: ", ex.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());
}
}
The code I use to accept the connection on the server:
static IPHostEntry ipHostInfo = Dns.GetHostEntry(Dns.GetHostName());
static IPAddress ipAddress = ipHostInfo.AddressList[0];
static IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 139);
static Socket listener = new Socket(ipAddress.AddressFamily,
SocketType.Stream, ProtocolType.Tcp);
try
{
listener.Bind(localEndPoint);
listener.Listen(100);
while (true)
{
allDone.Reset();
Console.WriteLine("Listening on: " + ipAddress);
listener.BeginAccept(
new AsyncCallback(AcceptCallback),
listener);
allDone.WaitOne();
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
static void AcceptCallback(IAsyncResult ar)
{
allDone.Set();
Socket listener = (Socket)ar.AsyncState;
Socket handler = listener.EndAccept(ar);
StateObject state = new StateObject();
state.workSocket = handler;
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
As I said this works flawlessly when both client and server application are executed on the same PC. If however they are on different machines the client gets a timout error within a couple of seconds.
Any help is appreciated, Thanks.

I am not able to receive my own Mcast packets C# UdpClient

I am not able to receive back my own packets send on multicast. i created two Udpclient receiver is to receive packets on multicast group and sender is to send packets. my packets are send to the group but i cannot receive back the packets send by me....
public void Join()
{
IPAddress ip1 = IPAddress.Any;
localep = new IPEndPoint(ip1, port);
Receiver = new UdpClient();
Receiver.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
Receiver.Client.Bind(localep);
Sender = new UdpClient();
Sender.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
Sender.Client.Bind(localep);
IPAddress ip = IPAddress.Parse(IP);
remoteep = new IPEndPoint(ip, port);
Sender.JoinMulticastGroup(ip);
Sender.EnableBroadcast = true;
Sender.MulticastLoopback = true;
Receiver.JoinMulticastGroup(ip);
Receiver.EnableBroadcast = true;
Receiver.MulticastLoopback = true;
udpState.ipEndpt = RemoteIpEndPoint;
udpState.udpClient = Receiver;
Receiver.BeginReceive(new AsyncCallback(GetMsg), udpState);
}
void GetMsg(IAsyncResult ar)
{
UdpClient udpClient = (UdpClient)((UdpState)(ar.AsyncState)).udpClient;
IPEndPoint ipEndpt = (IPEndPoint)((UdpState)(ar.AsyncState)).ipEndpt;
RecByte = Receiver.EndReceive(ar, ref ipEndpt);
}
//Sending packets logic
McastOTS.Sender.Send(sendBytes, sendBytes.Length, McastOTS.remoteep);

Seems to me all you need to do is call BeginReceive again after your EndReceive. Otherwise, you'll only get 1 message and won't see any others...
void GetMsg(IAsyncResult ar)
{
UdpClient udpClient = (UdpClient)((UdpState)(ar.AsyncState)).udpClient;
IPEndPoint ipEndpt = (IPEndPoint)((UdpState)(ar.AsyncState)).ipEndpt;
RecByte = Receiver.EndReceive(ar, ref ipEndpt);
Receiver.BeginReceive(GetMsg, udpState);
}

How to get IP address with a host name?

I am making a client that connect to a server that is locally hosted that gets stock numbers from the server. The program does work if i use this code below but the way it works is by getting the dns name so in theory it only takes www.website.com and I cant figure out how I can get it to recognize a normal ip of 127.0.0.1 or localhost IP:
IPHostEntry ipHostInfo = Dns.GetHostEntry("www.website.com");
IPAddress ipAddress = ipHostInfo.AddressList[0];
IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);
Attached is my attemp to get this to resolve the ip but I dont think I am approaching this right the full code can be seen here:StockReader Client Code
public class AsynchronousClient
{
private const int port = 21;
// 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
//******************ISSUE BEGINS HERE*********************************
string sHostName = Dns.GetHostName();
IPHostEntry ipHostInfo = Dns.GetHostEntry(sHostName);
IPAddress [] ipAddress = ipHostInfo.AddressList;
IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);
// Create a TCP/IP socket.
Socket client = new Socket(AddressFamily.InterNetwork,
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, "This is a test<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());
}
}

When you set the value of ipAddress, you can use the IPAddress.Parse method to pass in a string and retrieve an IPAddress object instead of using the domain name:
string ip = "127.0.0.1";
IPAddress address = IPAddress.Parse(ipAddress);
IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);

Try using string sHostName = "localhost";

// Establish the remote endpoint for the socket.
IPAddress ipAddress = IPAddress.Parse("127.0.0.1");
IPEndPoint remoteEP = new IPEndPoint(ipAddress, portnumber);
// Create a TCP/IP socket.
Socket s = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
s.Connect(remoteEP);