php 的 mail() 函数为广大用户在线发邮件提供了很大的便利，但mail()函数有一个非常大
的问题是它必须要有一台无需SMTP验证就可以发信的邮件服务器的支持，但如果一台邮件服
务器无需SMTP验证的话，就意味着互联网上的任何人都可以通过这台服务器来发垃圾邮件，
而垃圾邮件是国家明令禁止的，所以，为了杜绝有些人利用mail()函数来发垃圾邮件，我司的
服务器不支持mail()函数，同时，我们提供了相应的解决方案，有开发能力的用户可以利用PHP
的socket操作函数来自己开发邮件发送程序，如果没有相应有开发能力，也可以使用我们提供
的以下代码来发送邮件。

我们的解决方案中共用到两个页面，其中 smtp.class.php 是核心类文件，一般不需要作修改，
mailtest.php 是调用的例子，您只要将这个文件里相应的变量的值给改一下就可以变成您要用
的程序了。

smtp.class.php
=====================================================================================================================

<?
set_time_limit(120);

class smtp
{

/* Public Variables */

var $smtp_port;

var $time_out;

var $host_name;

var $log_file;

var $relay_host;

var $debug;

var $auth;

var $user;

var $pass;

var $sender;

/* Private Variables */
var $sock;

/* Constractor */

function smtp($relay_host = "", $smtp_port = 25,$auth = false,$user,$pass,$sender)
{
 $this->debug = FALSE;

 $this->smtp_port = $smtp_port;

 $this->relay_host = $relay_host;

 $this->time_out = 30; //is used in fsockopen()

 $this->auth = $auth;//auth

 $this->user = $user;

 $this->pass = $pass;

 $this->sender = $sender;

 $this->host_name = "localhost"; //is used in HELO command
 
 $this->log_file = "";

 $this->logs = ""; //记录跟服务器的交互过程

 $this->sock = FALSE;
}

/* Main Function */

function sendmail($to, $from, $subject = "", $body = "", $mailtype, $cc = "", $bcc = "", $additional_headers = "")
{
 $sent = TRUE;
 
 $mail_from = $this->get_address($this->strip_comment($from));

 $body = ereg_replace("(^|(\r\n))(\.)", "\1.\3", $body);

 $header .= "MIME-Version:1.0\r\n";

 if($mailtype=="HTML"){

  $header .= "Content-Type:text/html\r\n";
 }

 $header .= "To: ".$to."\r\n";

 if ($cc != "") {

  $header .= "Cc: ".$cc."\r\n";

 }

 //$header .= "From: $from<".$from.">\r\n";

 $header .= "From: ".$from."\r\n";

 $header .= "Subject: ".$subject."\r\n";

 $header .= $additional_headers;

 $header .= "Date: ".date("r")."\r\n";

 $header .= "X-Mailer: 72e.net (PHP/".phpversion().")\r\n";

 list($msec, $sec) = explode(" ", microtime());

 $header .= "Message-ID: <".date("YmdHis", $sec).".".($msec*1000000).".".$mail_from.">\r\n";

 $TO = explode(",", $this->strip_comment($to));

 if ($cc != "") {

  $TO = array_merge($TO, explode(",", $this->strip_comment($cc)));

 }

 if ($bcc != "") {

  $TO = array_merge($TO, explode(",", $this->strip_comment($bcc)));

 }

 
 foreach ($TO as $rcpt_to) {

  $rcpt_to = $this->get_address($rcpt_to);

  if (!$this->smtp_sockopen($rcpt_to)) {

   $this->log_write("Error: Cannot send email to ".$rcpt_to."\n");

   $sent = FALSE;

   continue;

     }

  if ($this->smtp_send($this->host_name, $mail_from, $rcpt_to, $header, $body)) {

   $this->log_write("E-mail has been sent to <".$rcpt_to.">\n");

  } else {

   $this->log_write("Error: Cannot send email to <".$rcpt_to.">\n");

   $sent = FALSE;

  }

  fclose($this->sock);

  $this->log_write("Disconnected from remote host\n");

 }

 return $sent;

}

 

/* Private Functions */

 

function smtp_send($helo, $from, $to, $header, $body = "")
{

 if (!$this->smtp_putcmd("HELO", $helo)) {

  return $this->smtp_error("sending HELO command");

 }

 #auth

 if($this->auth){

  if (!$this->smtp_putcmd("AUTH LOGIN", base64_encode($this->user))) {

   return $this->smtp_error("sending AUTH command");

  }

  if (!$this->smtp_putcmd("", base64_encode($this->pass))) {

   return $this->smtp_error("sending AUTH command");

  }

 }

 #

 //if (!$this->smtp_putcmd("MAIL", "FROM:".$from."")) {
    if (!$this->smtp_putcmd("MAIL", "FROM:<".$this->sender.">")) {
 
  return $this->smtp_error("sending MAIL FROM command");

 }

 if (!$this->smtp_putcmd("RCPT", "TO:<".$to.">")) {

  return $this->smtp_error("sending RCPT TO command");

 }

 if (!$this->smtp_putcmd("DATA")) {

  return $this->smtp_error("sending DATA command");

 }

 if (!$this->smtp_message($header, $body)) {

  return $this->smtp_error("sending message");

 }

 if (!$this->smtp_eom()) {

  return $this->smtp_error("sending <CR><LF>.<CR><LF> [EOM]");

 }

 if (!$this->smtp_putcmd("QUIT")) {

  return $this->smtp_error("sending QUIT command");

 }

 return TRUE;

}

function smtp_sockopen($address)
{

 if ($this->relay_host == "") {

  return $this->smtp_sockopen_mx($address);

 } else {

  return $this->smtp_sockopen_relay();

 }
}

function smtp_sockopen_relay()
{
 $this->log_write("Trying to ".$this->relay_host.":".$this->smtp_port."\n");

 $this->sock = @fsockopen($this->relay_host, $this->smtp_port, $errno, $errstr, $this->time_out);

 if (!($this->sock && $this->smtp_ok())) {

  $this->log_write("Error: Cannot connenct to relay host ".$this->relay_host."\n");

  $this->log_write("Error: "