อยากทราบวิธีการ Login โดยใช้ CURL ต่อเชื่อมต่อ server 2 ตัวครับ

curl_setopt($ch, CURLOPT_COOKIE, 'key=value;anotherkey=anothervalue');

<form name="login" action="http://www.gm4th.com/testlogin.php" method="post">
<table width="500" align="center">
  <tr>
    <td width="97">username :</td>
    <td width="391"><label for="username"></label>
    <input type="text" name="username" id="username" /></td>
  </tr>
  <tr>
    <td>password :</td>
    <td><label for="password"></label>
    <input type="text" name="password" id="password" /></td>
  </tr>
  <tr>
    <td>&nbsp;</td>
    <td><input type="submit" name="submit" id="submit" value="Submit" /></td>
  </tr>
</table>
</form>
<?php 
if($_POST['submit'])
{
	login_form($_POST['username'],$_POST['password']);
}

function login_form($username,$password)
{
	$ch = curl_init();
	curl_setopt($ch, CURLOPT_URL, 'http://www.ชื่อเว็บ.com/testlogin.php');
	curl_setopt($ch, CURLOPT_POST, 1);
	curl_setopt($ch, CURLOPT_POSTFIELDS, "username=".$username."&password=".$password."");
	curl_setopt($ch, CURLOPT_TIMEOUT, 60);
	curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 0); 
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
	curl_setopt($ch, CURLOPT_COOKIEJAR, 'cookie.txt');
	curl_setopt($ch, CURLOPT_COOKIEFILE, 'cookie.txt');
	curl_setopt($ch, CURLOPT_COOKIESESSION, 1);
	$ret = curl_exec($ch);

	// Close handle
	curl_close($ch);
	return $ret;
}

// Check GET
$username = check($_POST['username']);
$password = check($_POST['password']);
$hash	  = check($_POST['hash_code']);
$sys_id	  = check($_POST['system_id']);
$dt		  = check($_POST['dates']);
$tm = date("Y-m-d");
// GET RENT INFORMATION
$rent_sql = mysql_query("SELECT * FROM account_tbl WHERE username = '$username' AND password = '$password'");
$rent = mysql_fetch_array($rent_sql);
if(!$rent)
{
	echo "<script langquage='javascript'>
	alert('ข้อมูลเว็บตั้งค่าไม่ถูกต้องค่ะ');
window.location='http://www.เว็บ.com/';
</script>";
exit();
}
else
{
	if($tm > $rent['dt_stop'])
	{
		echo "<script langquage='javascript'>
		alert('ระบบเว็บหมดอายุแล้วค่ะ กรุณาต่ออายุด้วยค่ะ');
window.location='http://www.เว็บ.com/';
</script>";
exit();
	}
	else
	{
		setcookie('ifs_account', $_POST['user_id']);
		echo "<script langquage='javascript'>
		alert('เข้าสู่ระบบสำเร็จ');
window.location='http://127.0.0.1/index.php';
</script>";
exit();
	}
}