public function getServerSamlValidateURL()
    {
        phpCAS::traceBegin();
        // the URL is build only when needed
        if ( empty($this->_server['saml_validate_url']) ) {
            switch ($this->getServerVersion()) {
            case SAML_VERSION_1_1:
                $this->_server['saml_validate_url'] = $this->_getServerBaseURL().'samlValidate';
                break;
            }
        }

        $url = $this->_buildQueryUrl(
            $this->_server['saml_validate_url'],
            'TARGET='.urlencode($this->getURL())
        );
        phpCAS::traceEnd($url);
        return $url;
    }