function get_client_ip() {
    if (getenv('HTTP_CLIENT_IP') && strcasecmp(getenv('HTTP_CLIENT_IP'), 'unknown')) {
        $ip = getenv('HTTP_CLIENT_IP');
    }
    elseif (getenv('HTTP_X_FORWARDED_FOR') && strcasecmp(getenv('HTTP_X_FORWARDED_FOR'), 'unknown')) {
        $ip = getenv('HTTP_X_FORWARDED_FOR');
    }
    elseif (getenv('REMOTE_ADDR') && strcasecmp(getenv('REMOTE_ADDR'), 'unknown')) {
        $ip = getenv('REMOTE_ADDR');
    }
    elseif (isset ($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], 'unknown')) {
        $ip = $_SERVER['REMOTE_ADDR'];
    } else {
        $ip = 'unknown';
    }
    return ($ip);
}