Java send udp packet to dns server
<p>I am trying to send udp packet to specified dns server and receive a respone from dns server. </p>

<p>The problems is that I don't dont get the response from the server. I trying to receive a packet with my client socket but don't have any success.</p>

<p>Looking for help to fix this problem.</p>

<p>This is my UdpClient.java</p>

<pre><code>import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.Scanner;

class UdpClient
{
    public static void main (String args[]) throws Exception
    {
        Scanner scan = new Scanner(System.in);
        System.out.print("Enter a hostname: ");
        // host name
        String hostname = scan.next();
        // socket
        DatagramSocket clientSocket = new DatagramSocket();
        InetAddress ipAddress = InetAddress.getByName(hostname);
        String message = "0471001000000";
        byte[] data = message.getBytes(StandardCharsets.UTF_8);

        // datagram packet
        DatagramPacket sendPacket = new DatagramPacket(data, data.length, ipAddress, 53);
        // send the packet
        clientSocket.send(sendPacket);
        // set a receive timeout, 2000 milliseconds
        // packet for receive
        byte[] rdata = new byte[1024];
        DatagramPacket receivePacket = new DatagramPacket(rdata, rdata.length, ipAddress, 53);
        // wait for a response from the server
        clientSocket.receive(receivePacket);
        System.out.println("Host Name: " + ipAddress.getHostName());
        System.out.println("Canonical Host Name: " + ipAddress.getCanonicalHostName());
        System.out.println("Local Host: " + ipAddress.getLocalHost());
        System.out.println("Loopback Address: " + ipAddress.getLoopbackAddress());
        System.out.println("IPv4: " + ipAddress.getHostAddress());
        String serverMessage = new String(receivePacket.getData(), 0, receivePacket.getLength());
        System.out.println("FROM SERVER: " + serverMessage);
    }
}
</code></pre>