SMTP 이메일을 통해 PHP 로그인을 확인하는 방법

/**
* 通过邮件 验证登陆
* 这里要明白的是用户名是 带域名的：aaa@163.com
*/
function valideEmailLogin($user, $pass, $smtp_server= 'smtp.163.com', $port=25)
{
$handle = fsockopen($smtp_server, $port);
if(!$handle)
return false;
$mes = fgets($handle);
//echo $mes;
if(!$mes){
fclose($handle);
return false;
}
$status = explode(" ",$mes);
if($status[0] != 220) { //链接服务器失败
fclose($handle);
return false;
}
fwrite($handle, 'HELO mystore'."\r\n"); //表明身份,这里的mystore是随便写的
$mes = fgets($handle);
//echo $mes;
if(!$mes){
fclose($handle);
return false;
}
$status = explode(" ",$mes);
if($status[0] != 250) { //服务器HELO失败
fclose($handle);
return false;
}
fwrite($handle, 'AUTH LOGIN'."\r\n");
$mes = fgets($handle);
//echo $mes;
if(!$mes){
fclose($handle);
return false;
}
$status = explode(" ",$mes);
if($status[0] != 334) { //请求验证登陆失败
fclose($handle);
return false;
}
fwrite($handle,base64_encode($user)."\r\n");
$mes = fgets($handle);
//echo $mes;
if(!$mes){
fclose($handle);
return false;
}
$status = explode(" ",$mes);
if($status[0] != 334) { //验证用户名失败
fclose($handle);
return false;
}
fputs($handle,base64_encode($pass)."\r\n"); 
$mes = fgets($handle);
//echo $mes;
if(!$mes){
fclose($handle);
return false;
}
$status = explode(" ",$mes);
fclose($handle);
if($status[0] != 235) { //验证密码失败
return false;
}else{
return true;
}
}