class MySendMail {

private $_userName;

private $_password;

private $_sendServer;

protected $_port=25;

protected $_from;

protected $_to;

protected $_subject;

protected $_body;

protected $_socket;

protected $_errorMessage;

public function setServer($server, $username="", $password="", $port=25) {
$this->_sendServer = $server;
$this->_port = $port;
if(!empty($username)) {
$this->_userName = base64_encode($username);
}
if(!empty($password)) {
$this->_password = base64_encode($password);
}
return true;
}

public function setFrom($from) {
$this->_from = $from;
return true;
}

public function setReceiver($to) {
$this->_to = $to;
return true;
}

public function setMailInfo($subject, $body) {
$this->_subject = $subject;
$this->_body = base64_encode($body);
if(!empty($attachment)) {
$this->_attachment = $attachment;
}
return true;
}

public function sendMail() {
$command = $this->getCommand();
$this->socket();
foreach ($command as $value) {
if($this->sendCommand($value[0], $value[1])) {
continue;
}
else{
return false;
}
}
//其实这里也没必要关闭，smtp命令：QUIT发出之后，服务器就关闭了连接，本地的socket资源会自动释放
$this->close();
echo 'Mail OK!';
return true;
}

public function error(){
if(!isset($this->_errorMessage)) {
$this->_errorMessage = "";
}
return $this->_errorMessage;
}

protected function getCommand() {
$separator = "----=_Part_" . md5($this->_from . time()) . uniqid(); //分隔符
$command = array(
array("HELO sendmailrn", 250)
);
if(!empty($this->_userName)){
$command[] = array("AUTH LOGINrn", 334);
$command[] = array($this->_userName . "rn", 334);
$command[] = array($this->_password . "rn", 235);
}
//设置发件人
$command[] = array("MAIL FROM: _from . ">rn", 250);
$header = "FROM: _from . ">rn";
//设置收件人
$command[] = array("RCPT TO: _to . ">rn", 250);
$header .= "TO: _to . ">rn";
$header .= "Subject: " . $this->_subject ."rn";
$header .= "Content-Type: multipart/alternative;rn";
//邮件头分隔符
$header .= "t" . 'boundary="' . $separator . '"';
$header .= "rnMIME-Version: 1.0rn";
$header .= "rn--" . $separator . "rn";
$header .= "Content-Type:text/html; charset=utf-8rn";
$header .= "Content-Transfer-Encoding: base64rnrn";
$header .= $this->_body . "rn";
$header .= "--" . $separator . "rn";
//结束数据
$header .= "rn.rn";
$command[] = array("DATArn", 354);
$command[] = array($header, 250);
$command[] = array("QUITrn", 221);
return $command;
}

protected function sendCommand($command, $code) {
echo 'Send command:' . $command . ',expected code:' . $code . '
';
//发送命令给服务器
try{
if(socket_write($this->_socket, $command, strlen($command))){
//当邮件内容分多次发送时，没有$code，服务器没有返回
if(empty($code))  {
return true;
}
//读取服务器返回
$data = trim(socket_read($this->_socket, 1024));
echo 'response:' . $data . '

';
if($data) {
$pattern = "/^".$code."/";
if(preg_match($pattern, $data)) {
return true;
}
else{
$this->_errorMessage = "Error:" . $data . "|**| command:";
return false;
}
}
else{
$this->_errorMessage = "Error:" . socket_strerror(socket_last_error());
return false;
}
}
else{
$this->_errorMessage = "Error:" . socket_strerror(socket_last_error());
return false;
}
}catch(Exception $e) {
$this->_errorMessage = "Error:" . $e->getMessage();
}
}

private function socket() {
if(!function_exists("socket_create")) {
$this->_errorMessage = "Extension sockets must be enabled";
return false;
}
//创建socket资源
$this->_socket = socket_create(AF_INET, SOCK_STREAM, getprotobyname('tcp'));
if(!$this->_socket) {
$this->_errorMessage = socket_strerror(socket_last_error());
return false;
}
socket_set_block($this->_socket);//设置阻塞模式
//连接服务器
if(!socket_connect($this->_socket, $this->_sendServer, $this->_port)) {
$this->_errorMessage = socket_strerror(socket_last_error());
return false;
}
socket_read($this->_socket, 1024);
return true;
}

private function close() {
if(isset($this->_socket) && is_object($this->_socket)) {
$this->_socket->close();
return true;
}
$this->_errorMessage = "No resource can to be close";
return false;
}
}

$mail = new MySendMail();
$mail->setServer("XXXX", "XXX@XXX", "XXX");
$mail->setFrom("XXX@XX");
$mail->setReceiver("XXX@XX");
$mail->setMailInfo("test", "test");
$mail->sendMail();

来自：盛腾客户管理系统 详细介绍：www.shengtengcrm.com/model/