I am trying to send an udp packet from one computer to another in a local network. One computer is running Windows 10, other Ubuntu 18.04.
The code I have so far is this:
Server:
using System;
using System.Net.Sockets;
using System.Net;
namespace udpTest
{
class Program
{
static void Main(string[] args)
{
string hostName = Dns.GetHostName();
string ip = Dns.GetHostEntry(hostName).AddressList[0].ToString();
IPAddress ipadd = IPAddress.Parse(ip);
var serverEndPoint = new IPEndPoint(ipadd, 20020);
var udp = new UdpClient(ipadd.ToString(), 20020);
while (true) {
var recvData = udp.ReceiveAsync().Result;
System.Console.WriteLine($"received: {recvData.Buffer}");
}
}
}
}
Client:
using System;
using System.Net.Sockets;
using System.Net;
namespace C_
{
class Program
{
static void Main(string[] args)
{
var udp = new UdpClient();
var bytes = BitConverter.GetBytes(420);
var i = udp.SendAsync(bytes, bytes.Length, "fe80::7077:8d67:4984:c9bc%43", 20020 ).Result;
System.Console.WriteLine($"sent: {i}");
}
}
}
(I changed the ipv6 address a bit but format is exactly the same).
I get no errors when sending or anything, it just goes through but the server does not catch it. I have no idea what I am doing wrong. So any pointers would be most appreciated.
Edit: updated code works within lan, but not outside LAN.
Client:
static void Main(string[] args)
{
var udp = new UdpClient("192.168.1.117", 20020);
var bytes = BitConverter.GetBytes(420);
var i = udp.SendAsync(bytes, bytes.Length).Result;
System.Console.WriteLine($"sent: {i}");
}
Server:
static void Main(string[] args)
{
var serverEndPoint = new IPEndPoint(IPAddress.Any, 20020);
var udp = new UdpClient(serverEndPoint);
while (true) {
var recvData = udp.ReceiveAsync().Result;
System.Console.WriteLine($"received: {recvData.Buffer}");
}
}
first try IPAddress.Any since using the first IP address from Dns.GetHostEntry(hostName).AddressList[0].ToString(); is not guaranteed to be the IPv6 address you are using, specially if the computer has more than one network adapter.
Second is using the serverEndPoint you created for the UdpClient constructor
// Use IPAddress.Any
IPAddress ipadd = IPAddress.Any;
var serverEndPoint = new IPEndPoint(ipadd, 20020);
// Use the serverEndPoint for the UP
var udp = new UdpClient(serverEndPoint);
Third, check the server's firewall settings and make sure you allow incoming UDP messages on port 20020 (by default on both Windows and Ubuntu it is not allowed). And check the client firewall settings and make sure outgoing UDP messages on port 20020 are allowed (by default on both Windows and Ubuntu it is allowed).
Related
I have searched everywhere but couldn't find as they are all answering to send message to all clients. What I want to achieve is multiple clients request to server to request data from another client and other client sends data to server telling it that data is for requesting client and so. I don't know how to achieve this. I'm new to this.
What I want to achieve:
I have tried with Data sending client to listen and requesting client to connect to it and transfer data. I have achieved this on local network but to make it work online it needs port forwarding and my user will be a lot of different people so port forwarding is not possible for every user. So I can rent a server which will act as a center of transfer. I programmed a test server in console which will listen to a server IP:port X and accept new clients and their data on port X and forward it to server IP:port Y but what this does is send data to all clients on port Y. I cannot send it to clients public ip address directly for obvious reasons. I understand that all the requesting clients are connected to port Y but I cannot create and assign new ports to all the clients interacting. So I want a way to determine how to request and receive the data without the need of assigning or creating new ports to different clients on same server.
What I have tried:
Server code
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
namespace Test___server
{
class server
{
public static string serverIP = "192.168.0.102";
static void Main(string[] args)
{
Thread listenSendingThread = new Thread(listenSending);
listenSendingThread.IsBackground = true;
listenSendingThread.Start();
Thread listenReceivingThread = new Thread(listenReceiving);
listenReceivingThread.IsBackground = true;
listenReceivingThread.Start();
Console.ReadKey();
}
public static List<TcpClient> listSending = new List<TcpClient>();
public static List<TcpClient> listReceiving = new List<TcpClient>();
public static TcpClient clientSending = null;
private static void listenSending()
{
TcpListener listenerSending = new TcpListener(IPAddress.Parse(serverIP), 5319);
listenerSending.Start();
Console.WriteLine("Server listening to " + serverIP + ":5319");
while(true)
{
clientSending = listenerSending.AcceptTcpClient();
listSending.Add(clientSending);
Console.WriteLine("Sender connection received from " + clientSending.Client.RemoteEndPoint);
}
}
private static void send()
{
StreamWriter sw = new StreamWriter(clientSending.GetStream());
sw.WriteLine(message);
sw.Flush();
Console.WriteLine("Message sent!");
}
public static string message = string.Empty;
private static void listenReceiving()
{
TcpListener listener = new TcpListener(IPAddress.Parse(serverIP), 0045);
listener.Start();
Console.WriteLine("Server listening to " + serverIP + ":0045");
while (true)
{
TcpClient client = listener.AcceptTcpClient();
listReceiving.Add(client);
Console.WriteLine("Receiver connection received from " + client.Client.RemoteEndPoint);
StreamReader sr = new StreamReader(client.GetStream());
message = sr.ReadLine();
send();
}
}
}
}
Requesting client code
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace Test____admin
{
class admin
{
static void Main(string[] args)
{
Console.WriteLine("Begin");
string serverIP = "192.168.0.102";
System.Net.Sockets.TcpClient clientSocket = new System.Net.Sockets.TcpClient();
clientSocket.Connect(serverIP, );
Console.WriteLine("Connected");
while (true)
{
Console.WriteLine("Reading");
StreamReader sr = new StreamReader(clientSocket.GetStream());
Console.WriteLine("Message: " + sr.ReadLine());
}
}
}
}
Request satisfying client code
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net.Sockets;
using System.Text;
using System.Threading.Tasks;
namespace Test___client
{
class client
{
public static string serverIP = "192.168.0.102";
static void Main(string[] args)
{
clientConnect();
}
private static void clientConnect()
{
try
{
TcpClient client = new TcpClient(serverIP, 0045);
StreamWriter sw = new StreamWriter(client.GetStream());
sw.WriteLine("Karan!");
sw.Flush();
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}
}
}
}
You are using a very low-level API, and doing it the right way is challenging. Instead, try YARP as a reverse proxy. The requesting client should notify the reverse proxy about the desired destination client. One option is sending the destination client name in the request header. You will also need to split a single server request into multiple client requests, then merge their responses into a single one. You can achieve it by implementing Transphorms.
I'm not sure this approach applies to your situation because clients should implement server API using REST, Grpc or any other supported technology.
I am trying to receive socket communication with C # on Unity.
The following unityRecieve.cs will result in an error if Send.py is interrupted.
Send.py
import socket
import random
HOST = '127.0.0.1'
PORT = 50007
client = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
while True:
a = random.randrange(3)
result = str(a)
print(a)
client.sendto(result.encode('utf-8'),(HOST,PORT))
time.sleep(2.0)
unityRecieve.cs
using UnityEngine;
using System.Net;
using System.Net.Sockets;
using System.Text;
public class unityRecieve : MonoBehaviour
{
static UdpClient udp;
void Start()
{
int LOCA_LPORT = 50007;
udp = new UdpClient(LOCA_LPORT);
udp.Client.ReceiveTimeout = 100;
}
void Update()
{
IPEndPoint remoteEP = null;
byte[] data = udp.Receive(ref remoteEP);
string text = Encoding.UTF8.GetString(data);
Debug.Log(text);
}
}
https://jump1268.hatenablog.com/entry/2018/11/25/143459
How can I make unitiRecieve.cs keep running without giving an error message when Send.py is interrupted?
Not sure if you have considered exception handling. If you did not, this might point you in the right direction.
https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/try-catch
I have this code in a console app:
using System.Text;
using System.Diagnostics;
using System.Net.Sockets;
using System.Net;
namespace ConsoleApplication3
{
class Program
{
static void Main(string[] args)
{
byte[] data = ASCIIEncoding.ASCII.GetBytes("test message");
string IP = "192.168.1.22";
int Port = 2390;
IPEndPoint endPoint = new IPEndPoint(IPAddress.Parse(IP), Port);
Socket client = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
SocketAsyncEventArgs socketEventArg = new SocketAsyncEventArgs();
socketEventArg.RemoteEndPoint = endPoint;
socketEventArg.SetBuffer(data, 0, data.Length);
client.SendToAsync(socketEventArg);
Debug.WriteLine("sent");
}
}
}
and this code in the Windows Universal App:
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using System.Net;
using System.Net.Sockets;
using System.Diagnostics;
using System.Text;
namespace App6
{
public sealed partial class MainPage : Page
{
public MainPage()
{
this.InitializeComponent();
byte[] data = ASCIIEncoding.ASCII.GetBytes("test message");
string IP = "192.168.1.22";
int Port = 2390;
IPEndPoint endPoint = new IPEndPoint(IPAddress.Parse(IP), Port);
Socket client = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
SocketAsyncEventArgs socketEventArg = new SocketAsyncEventArgs();
socketEventArg.RemoteEndPoint = endPoint;
socketEventArg.SetBuffer(data, 0, data.Length);
client.SendToAsync(socketEventArg);
Debug.WriteLine("sent");
}
}
}
As you can see the content of both is nearly identical.
The IP I set it to send to is a program I'm running on a different computer that I have confirmed works. When I run the console application, it displays the data I sent properly on the program on the other computer, and the console application prints out "sent" on the debug console as it should. The Universal Windows App similarly prints out "sent", however the packet never reaches the other computer.
I checked using WireShark (a network analysis/packet sniffing tool) and it appears that when I use the console application, a UDP packet is sent, but when I use the Universal Windows app, no UDP packets are found.
I am running both programs from Visual Studio 2015 in debug mode, and I can't think of any reason why it wouldn't be working.
Any suggestions or ideas would be helpful!
Just a guess - have you added the internetClient capability to your app? https://msdn.microsoft.com/en-us/library/windows/apps/mt280233.aspx
i'm trying to make an application for my laptop which in case i forgot to log off, i can use my smarthphone to log off by using a specific app for that. So i was thinking usually if you have a router... you have a problem cause you don't have the external ip which you can use, and the port. For that i used this function to get the external ip.
public string adresaIP()
{
UTF8Encoding utf8 = new UTF8Encoding();
WebClient clientWeb = new WebClient();
String adresaIP = utf8.GetString(clientWeb.DownloadData("http://bot.whatismyipaddress.com"));
return adresaIP;
}
But when i try to use te IpEndPoint it dosen't work it give's me an exception Error and i don't know were i did wrong.
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.Net.Sockets;
using System.IO;
namespace bluetooth_LogOff
{
public partial class Form1 : Form
{
static byte[] buffer { get; set; }
static Socket soket;
public Form1()
{
InitializeComponent();
try
{
string ip = adresaIP();
soket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
//soket.Bind(new IPEndPoint(IPAddress.Parse(ip),1234)); <<-- in this way dosen't work
soket.Bind(new IPEndPoint(IPAddress.Parse("127.0.0.1"),1234)); // <<- in this way it works....
soket.Listen(100);
Socket accept = soket.Accept();
buffer = new byte[accept.SendBufferSize];
int bytesRead = accept.Receive(buffer);
byte[] format = new byte[bytesRead];
for (int i = 0; i < bytesRead; i++)
{
format[i] = buffer[i];
}
string primescMesaj = Encoding.ASCII.GetString(format);
MessageBox.Show(primescMesaj);
soket.Close();
accept.Close();
}
catch (Exception messaj)
{
MessageBox.Show(messaj.ToString());
}
}
private void button1_Click(object sender, EventArgs e)
{
label1.Text = adresaIP();
}
public string adresaIP()
{
UTF8Encoding utf8 = new UTF8Encoding();
WebClient clientWeb = new WebClient();
String adresaIP = `utf8.GetString(clientWeb.DownloadData("http://bot.whatismyipaddress.com"));`
return adresaIP;
}
}
}
But the funny thing is if i put the addres like "127.0.0.1" It works, but if i put the string addres it dosen't
You cannot bind to the external address that address belongs to the router.
You should bind to address 0.0.0.0 (all addresses) on your laptop and configure your router to forward the laptop port (or use UPnP).
The reason you cannot access your laptop directly is because your router, like most routers is a NAT (network address translation) router. It allows several computers to hide behind a single IP address. So the router will have a public IP address and your laptop and other devices behind the router will have a private IP address (such as those in the range 192.168.x.x)
Most NAT routers can be configured with static port forwarding; i.e. the port in a specific private address is reflected in the same or a different port in the public IP.
This allows access to internal devices from the public internet. UPnP is a protocol that does the same thing, but does not require manual configuration on the router. UPnP is usually how P2P applications and some multi-player games gain public accessible ports without human intervention. It is also why UPnP may be considered a security hazard since the computer owner may not be aware of such forwarding.
We use SharpSVN to programmatically access SVN repositories. Now we have the problem that the access to local repositories via svn:// or http:// urls is very slow - every access needs at least one second, and our app needs to fetch a bunch of properties and directory listings.
We could reproduce the problem on two different machines, both are Windows 7 32 bit and are in the same domain. The SVN servers are VisualSVN 2.1.9 for http:// urls and the CollabNet 1.6.17 for svn:// urls. It appears for connections via "localhost" and via the host name. It appears in our C# application, as well as a small testbed app using IronPython and when calling the SharpSvn svn.exe command.
This problem does not happen when accessing when accessing remote repositories (Both a linux and a windows XP server) - here, each access is between 0.01 and 0.08 secs, which is expected due to network latency. The Problem also does not happen when acessing the local repositories via file:// urls or when accessing the repositories via "native" svn command line tools from CollabNet.
Now my question is: Has Windows 7 or .NET or SharpSVN some built-in limit which only applies to localhost connections?
(Addition: I now found out that this limit also applies when connecting via a small C# test program using System.Net.Sockets.TcpClient:
Server:
using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
namespace TcpSpeedServer
{
class Program
{
public static void Main()
{
Int32 port = 47011;
IPAddress localAddr = IPAddress.Parse("127.0.0.1");
var server = new TcpListener(localAddr, port);
server.Start();
Console.WriteLine("Listening on {0} : {1}", localAddr, port);
ulong count = 0;
// Enter the listening loop.
while(true)
{
using (var client = server.AcceptTcpClient()) {
Console.WriteLine("Connected: {0} {1}!", count, client.Client.RemoteEndPoint);
count += 1;
using (var stream = client.GetStream()) {
using (StreamWriter writer = new StreamWriter(stream))
using (StreamReader reader = new StreamReader(stream))
{
string query = reader.ReadLine();
writer.WriteLine("GET / HTTP/1.0");
writer.WriteLine();
writer.Flush();
}
}
}
}
}
}
}
Client:
using System;
using System.Collections.Generic;
using System.IO;
using System.Net.Sockets;
using System.Threading;
namespace TcpSpeedTest
{
class Program
{
const bool ASYNC = false;
static DateTime s_now;
public static void Main(string[] args)
{
var liste = new List<object>();
s_now = DateTime.Now;
for (int i=0; i < 100; i += 1) {
if (ASYNC)
ThreadPool.QueueUserWorkItem(connect, i);
else
connect(i);
}
Console.WriteLine("outer: " + (DateTime.Now - s_now));
Console.ReadLine();
}
private static void connect(object i)
{
DateTime now = DateTime.Now;
using (TcpClient client = new TcpClient("localhost", 47011))
{
var stream = client.GetStream();
using (StreamWriter writer = new StreamWriter(stream))
using (StreamReader reader = new StreamReader(stream))
{
writer.WriteLine("GET / HTTP/1.0");
writer.WriteLine();
writer.Flush();
string result = reader.ReadLine();
}
}
Console.WriteLine(string.Format("inner: {0} - {1} - {2}", i, DateTime.Now - now, DateTime.Now - s_now));
}
}
}
So this problem seems not to be subversion specific.)
Addition2: When running the client under Mono 2.10 for windows, the problem does not appear. So it seems to be specific to .NET framework.
Addition3: It seems to be an IPv6 related problem. The server only listens on IPv4, but the hostname also resolves to IPv6. Now it seems that the OS code internally tries the IPv6 connection, and after getting the connection reset, waits 1 sec before falling back to IPv4. And this game is repeated for every single connection attempt. http://msdn.microsoft.com/en-us/library/115ytk56.aspx documents that for TcpClient (thanks to Andreas Johansson from the MSDN forums for the hint!), and it seems that the APR used by Apache internally uses a similar mechanism.
Addition 3 is also the solution to your problem. To fix this, either make DNS/hosts file only resolve to an IPv4 address, or make the IPv6 server(s) work.
You can enter in C:\Windows\System32\drivers\etc\hosts something like:
127.0.0.1 localhost-ipv4
And then use that name to connect.
You can also make svnserve listen to IPv6 addresses. A quick search for svnserve options [revealed][1] that it defaults to IPv6, so in its startup parameters is probably a --listen-host. Try removing that, or when it's not present forcing it to run at IPv6.
The same can be done for the Apache webserver:
Listen 0.0.0.0:80
Listen [::]:80