protected function mod_login($user)
    {
        $login_lc = $this->rc->config->get('login_lc');

        if ($login_lc === true || $login_lc == 2) {
            $user = mb_strtolower($user);
        }
        // lowercase domain name
        else if ($login_lc && strpos($user, '@')) {
            list($local, $domain) = explode('@', $user);
            $user = $local . '@' . mb_strtolower($domain);
        }

        return $user;
    }