This program runs a server that give you the IP address of every client that try to connect. Its quite useful as a whatismyip service on a local network.

Main.java

package fr.stackr.java.gimmeyourip;

import java.io.IOException;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;

/**
 * This program runs a server that give you the IP address of every client that
 * try to connect. Its quite useful as a whatismyip service on a local network.
 * 
 * @author Romain Bochet
 */
public class Main {

	/**
	 * Translation of IP in ascii
	 */
	private final static int PORT_NUMBER = 7380;

	/**
	 * Endless while waiting for new connections.
	 * 
	 * @param args
	 *            Not used
	 * @throws IOException
	 *             If the socket initialisation fails
	 */
	public static void main(String[] args) throws IOException {
		System.out.println("GimmeMyIP started (host: "
				+ InetAddress.getLocalHost() + ") -- listen on port "
				+ Main.PORT_NUMBER);

		ServerSocket srv = new ServerSocket(Main.PORT_NUMBER);
		while (true) {
			Socket socket = srv.accept();
			System.out.println("Client connected: "+socket.getInetAddress());
			socket.close();
		}
	}
}