private void checkInternetConnection() {
        checkingLabel.setText("Checking network configuration...");

         try {
                Configuration.hostname = InetAddress.getLocalHost().getHostName();
            } catch ( UnknownHostException ex ) {
                checkingLabel.setText("Checking network configuration...FAILED");
                System.err.println(ex.getMessage());

                JOptionPane.showMessageDialog(sif, "The installer was not able to get current host's hostname.\n" +
                                                   "Please make sure that the networking of current host is properly configured\n" +
                                                   "Running \"/etc/init.d/network restart\" may fix the problem.\n\n" +
                                                   "Press OK to exit the installer", "Error - Failed to get the hostname of this computer", JOptionPane.ERROR_MESSAGE);
                System.exit(6);

            }




        File checksumsFile = new File("checksums");
        File checksumsOldFile = new File("checksumsOld");
        File checksumsNewFile = new File("checksumsServer");

        if ( checksumsFile.exists() ) {
            NativeCalls.copyFile(checksumsFile, checksumsOldFile);
        }

        if ( checksumsNewFile.exists())
            checksumsNewFile.delete();
        

        checkingLabel.setText("Checking internet connection...");

        try {
            Download d = new Download(new URL("http://users.loni.ucla.edu/~pipeline/dps/checksumsServer"));
            d.addObserver(this);

            if ( d.getStatus() == Download.COMPLETE ) {
                System.err.println("Invalid file ");
            }

        } catch ( MalformedURLException ex ) {
            ex.printStackTrace();
        }

    }