gistfile1.txt

    /**
     * Determine if some other VPN is running
     */
    public static boolean isVpnConnected() {
        try {
            final List<NetworkInterface> interfaces = Collections.list(NetworkInterface.getNetworkInterfaces());
            for (final NetworkInterface networkInterface : interfaces) {
                final String name = networkInterface.getDisplayName();
                final boolean isUp = networkInterface.isUp();
                LOG.info("Interface: {} connected = {}", name, isUp);
                if (StringUtils.startsWithIgnoreCase(name, "tun") && isUp) {
                    return true;
                }
            }
        } catch (SocketException ex) {
            LOG.debug("Error while checking if other VPN is connected\n", ex);
        }
        return false;
    }