Implementation of User Datagram Protocol (UDP) with Domain Name System (DNS)

This is a java program to implement DNS through UDP, provides a DNS server and a client, were the client requests for the IP Address of the specific Domain name to the DNS server

UDPserver.java:

import java.io.*;

import java.net.*;

class UDPserver

{

public static DatagramSocket ds;

public static byte buffer[]=new byte[1024];

public static int clientport=7898,serverport=7908;

public static void main(String args[])throws Exception

{

ds=new DatagramSocket(clientport);

System.out.println("press ctrl+c to quit the program");

BufferedReader dis=new BufferedReader(new InputStreamReader(System.in));

InetAddress ia=InetAddress.getLocalHost();

while(true)

{

DatagramPacket p=new DatagramPacket(buffer,buffer.length);

ds.receive(p);

String psx=new String(p.getData(),0,p.getLength());

System.out.println("Client:"+ psx);

InetAddress ib=InetAddress.getByName(psx);

System.out.println("Server output:"+ib);

String str=dis.readLine();

if(str.equals("end"))
break;

buffer=str.getBytes();

ds.send(new DatagramPacket(buffer,str.length(),ia,serverport));

}

}

}

UDPclient.java:

import java .io.*;

import java.net.*;

class UDPclient

{

public static DatagramSocket ds;

public static int clientport=7898,serverport=7908;

public static void main(String args[])throws Exception

{

byte buffer[]=new byte[1024];

ds=new DatagramSocket(serverport);

BufferedReader dis=new BufferedReader(new InputStreamReader(System.in));

System.out.println("server waiting");

InetAddress ia=InetAddress.getLocalHost();

while(true)

{

System.out.println("Client:");

String str=dis.readLine();

if(str.equals("end"))

break;

buffer=str.getBytes();

ds.send(new DatagramPacket(buffer,str.length(),ia,clientport));

DatagramPacket p=new DatagramPacket(buffer,buffer.length);

ds.receive(p);

String psx=new String(p.getData(),0,p.getLength());

System.out.println("Server:"+ psx);

}

}

}

Output: