SPF 등록하고 화이트 도메인 등록되있는 상태에선 가는거 같습니다

화이트 도메인 등록을 하지 않더라도 네이버에 문의 메일 한통이면 차단해제 해 줍니다..

만약 XE에서 mail()함수 대신 qmail을 사용한 방법으로도 안되시는거라면 직접 소켓에 필요한 정보만 다뤄서 보내보세요. 아래는 nmsXE, www.xeuser.org에 사용하고 있는 내용입니다. 네이버는 물론, 다음 등도 첨부파일 포함으로 잘 갑니다.

        /**
         * @brief 메일 보내기 전 정보 초기화
         **/
        function sendMail($args = false) {
            $oModuleModel = &getModel('module');
            $oNms = $oModuleModel->getModuleConfig('nms');

            $mail = new Mail;
            $mail->smtp_secure = ($oNms->smtp_config->smtp_secure)?$oNms->smtp_config->smtp_secure:'tcp';
            $mail->smtp_server = $oNms->smtp_config->smtp_server;
            $mail->smtp_port = $oNms->smtp_config->smtp_port;
            $mail->user = $oNms->smtp_config->smtp_user;
            $mail->pass = $oNms->smtp_config->smtp_pass;

            $mail->setSender($args->sender->name,$args->sender->email);
            $mail->setTitle($args->title);
            $mail->setContent($args->content);
            $mail->setContentType('html');

            // 첨부파일 정리
            if(is_array($args->attach)) {
                foreach($args->attach as $key => $attach) {
                    $mail->attach[] = $attach;
                }
            }

            // 메일 보냄
            foreach($args->receiptor as $key => $receiptors) {
                $mail->setReceiptor($receiptors->name, $receiptors->email);
                $this->_sendMail($mail);
            }
        }

        /**
         * @brief 메일 보내기
         **/
        function _sendMail($mail) {
            // 영문이외의 문자 이름이 출력되도록 함
            $sender_email = sprintf("%s <%s>", '=?utf-8?b?'.base64_encode($mail->sender_name).'?= ', $mail->sender_email);
            $receiptor_email = sprintf("%s <%s>", '=?utf-8?b?'.base64_encode($mail->receiptor_name).'?= ', $mail->receiptor_email);

            $boundary = "----==".uniqid(rand(),true); // 바운드를 초기화한다
            $eol = $GLOBALS['_qmail_compatibility'] == 'Y' ? "\n" : "\r\n";

            $headers = sprintf(
                "MIME-Version: 1.0".$eol.
                "Content-Type: Multipart/mixed;".$eol."\tboundary=\"%s\"".$eol.
                "Subject: %s".$eol.
                "From: %s".$eol.
                "To: %s".$eol.$eol,
                $boundary,
                $mail->getTitle(),
                $sender_email,
                $receiptor_email
            );

            $body = sprintf(
                "--%s".$eol.
                "Content-Type: text/html; charset=utf-8".$eol.
                "Content-Transfer-Encoding: base64".$eol.$eol.
                "%s".$eol.$eol,
                $boundary,
                $mail->getHTMLContent()
            );

            // 첨부파일
            if(is_array($mail->attach)) {
                foreach($mail->attach as $key => $path) {
                   $name = basename($path->filename);
                   $file = FileHandler::readFile($path->fileurl);

                   $fileBody = sprintf(
                        "--%s".$eol.
                        "Content-Type: application/octet-stream".$eol.
                        "Content-Transfer-Encoding: base64".$eol.
                        "Content-Disposition: attachment; filename=\"%s\"".$eol.$eol.
                        "%s",
                        $boundary,
                        $name,
                        chunk_split(base64_encode($file))
                    );

                    $body .= $fileBody;
                }
            }

            // 인증방식으로 메일을 보냄
            if($smtp_socket = @fsockopen($mail->smtp_secure."://".$mail->smtp_server, $mail->smtp_port, $errno, $errstr, 5)) {
                $this->_getMail($smtp_socket);
                @fputs($smtp_socket, 'HELO '.$mail->smtp_secure."://".$mail->smtp_server.$eol);
                $this->_getMail($smtp_socket);
                @fputs($smtp_socket, 'AUTH LOGIN'.$eol);
                $this->_getMail($smtp_socket);
                @fputs($smtp_socket, base64_encode($mail->user).$eol);
                $this->_getMail($smtp_socket);
                @fputs($smtp_socket, base64_encode($mail->pass).$eol);
                $this->_getMail($smtp_socket);
                @fputs($smtp_socket, 'MAIL From: <'.$mail->sender_email.'>'.$eol);
                $this->_getMail($smtp_socket);
                @fputs($smtp_socket, 'RCPT To: <'.$mail->receiptor_email.'>'.$eol);
                $this->_getMail($smtp_socket);
                @fputs($smtp_socket, 'DATA'.$eol);
                $this->_getMail($smtp_socket);
                $content = sprintf(
                    "%s".$eol.
                    "%s".$eol.
                    ".".$eol,
                    $headers,
                    $body
                );
                @fputs($smtp_socket, $content);
                $this->_getMail($smtp_socket);
                @fputs($smtp_socket, 'QUIT'.$eol);
                @fclose($smtp_socket);
            }
        }

        /**
         * @brief 상대방의 응답을 기다립니다.(gmail등 인증 방식 사용시)
         **/
        function _getMail($socket = null) {
            if(!$socket) return;
            $i = 0;
            $response = '-';
            while($response == '-' && $i<10) {
                $response = @fgets($socket, 256);
                if($response) $response = substr($response,3,1);
                else return;

                $i++;
            }
        }

저는 아직 단체메일 보내는 막 큰 커뮤니티 아니고 가입인증메일 정도 소규모로 보내서 그런진 몰라도 화이트도메인이나 여타 다른 인증을 받지 않은 채 그냥 유동IP로 운영하는데도 네이버 메일로 메일이 잘 갑니다...

참고하세요 :)