ARPClient.java

import java.net.*;
import java.util.Scanner;

public class ARPClient {
    public static void main(String[] args) throws Exception {
        DatagramSocket ds = new DatagramSocket();
        InetAddress serverAddr = InetAddress.getByName("localhost");
        int serverPort = 9091;

        Scanner sc = new Scanner(System.in);
        System.out.print("Enter IP to resolve (e.g., 192.168.1.1): ");
        String ip = sc.nextLine();

        // Send ARP request as "REQUEST:<IP>"
        byte[] request = ("REQUEST:" + ip).getBytes();
        ds.send(new DatagramPacket(request, request.length, serverAddr, serverPort));
        System.out.println("Sent ARP Request for " + ip);

        // Receive reply
        byte[] buf = new byte[1024];
        DatagramPacket dp = new DatagramPacket(buf, buf.length);
        ds.receive(dp);
        String reply = new String(dp.getData(), 0, dp.getLength());
        System.out.println("Received ARP Reply: " + reply);

        ds.close();
    }
}