Ping using java

Question

I used the followning program ping.java to ping a remote host.
It needs the host name as argument.
I tried using
java ping xxx.xxx.xx.xxx
but it always reports that the host is down, while it actually isnt.
Any ideas as to why this may not be working?
(xx.. is the ip address of the remote machine)
import java.io.*;
import java.net.*;
public class ping {
public final static int ECHO_PORT = 7;
public static void main(String argv[]) {
if (argv.length != 1) {
System.out.println("Usage: java ping hostname");
System.exit(0);
if (alive(argv[0]))
{ System.out.println(argv[0] + " is alive");
} else{
System.out.println("No response from " + argv[0] +". Host is down or does not exist");
public static boolean alive(String host)
Socket pingSocket = null;
try {
pingSocket = new Socket(host, ECHO_PORT);
} catch (UnknownHostException e) {
System.err.println("UnknownHostException: " +e);
} catch (IOException io) {
System.out.println("IOException: " + io);
if (pingSocket != null)
{  try {
pingSocket.close();
} catch (IOException e)
{ System.err.println("IOException: " + e);
return true;
} else
{ return false;

Answer 1

That is factually accurate, but I believe irrelevant,
because one cannot accurately distinguish the two
cases.yes, in both cases a IOException is thrown, and the obly difference i've found is the message ("connection timed out" or "connection refused"), don't know if this is accurate, guess not.
anyway, i feel it is not a proper way to do this, go opening tcp connections. but is the only way i know...