Sending emails through curl smtp in php_PHP tutorial

$ telnet Email SMTP service address 25
Trying email service IP address...
Connected to Email SMTP service address.
Escape character is '^]'.
exchange email server addressMicrosoft ESMTP MAIL Service ready at Sat, 2 Jun 2012 15:02:12 +0800
EHLO 127.0.0.1
-exchange Email Server Address Hello [Email Service IP Address]
-SIZE
-PIPELINING
-DSN
-ENHANCEDSTATUSCODES
-X-ANONYMOUSTLS
-AUTH NTLM LOGIN
-X-EXPS GSSAPI NTLM
-8BITMIME
-BINARYMIME
-CHUNKING
-XEXCH50
XRDST
AUTH LOGIN
VXNlcm5hbWU6
Username (base64_encode)
UGFzc3dvcmQ6
Password (base64_encode)
2.7.0 Authentication successful
MAIL FROM: outbox address
2.1.0 Sender OK
RCPT TO:Inbox address
2.1.5 Recipient OK
DATA
Start mail input; end with .
To send Content (there are many related specifications here)
.
2.6.0 <0b476f30-3b96-4e3d-84d2-395a96d34000@exchange email server address> Queued mail for delivery
QUIT
2.0.0 Service closing transmission channel
Connection closed by foreign host.

header("content-type:text/html;charset=utf-8");
$smtp = array(
"url " => "Email SMTP server address",
"port" => "Email SMTP server port", // Generally 25
"username" => "Username",
" password" => "Password",
"from" => "Sending address",
"to" => "Receiving address",
"subject" => "Test Title",
"body" => "Test the content"
);
$CRLF = "rn";
$test = "";
$curl = curl_init( );
curl_setopt($curl, CURLOPT_URL, $smtp['url']);
curl_setopt($curl, CURLOPT_PORT, $smtp['port']);
curl_setopt($curl, CURLOPT_TIMEOUT, 10);
function inlineCode($str){
$str = trim($str);
return $str?'=?UTF-8?B?'.base64_encode($str).' ?= ':'';
}
function buildHeader($headers){
$ret = '';
foreach($headers as $k=>$v){
$ret.=$k.': '.$v."n";
}
return $ret;
}
//
$header = array(
' Return-path'=>'<'.$smtp['from'].'>',
'Date'=>date('r'),
'From'=> '<'.$smtp['from'].'>',
'MIME-Version'=>'1.0',
'Subject'=>inlineCode($smtp['subject' ]),
'To'=>$smtp['to'],
'Content-Type'=>'text/html; charset=UTF-8; format=flowed',
'Content-Transfer-Encoding'=>'base64'
);
$data = buildHeader($header).$CRLF.chunk_split(base64_encode($smtp['body']));
$content = "EHLO ".$smtp["url"].$CRLF; // Hello first
$content .= "AUTH LOGIN".$CRLF.base64_encode($smtp["username"]). $CRLF.base64_encode($smtp["password"]).$CRLF; // Verify login
$content .= "MAIL FROM:".$smtp["from"].$CRLF; // Sending address
$content .= "RCPT TO:".$smtp["to"].$CRLF; // Recipient address
$content .= "DATA".$CRLF.$data.$CRLF." .".$CRLF; // Send content
$content .= "QUIT".$CRLF; // Exit
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true); // curl receives return data
curl_setopt ($curl, CURLOPT_CUSTOMREQUEST, $content);
$test = curl_exec($curl);
var_dump($test);
echo "
rn";
var_dump( $content);
// End
curl_close($curl);