PHP script being called by 2 IPs (1 Viewer)

<?PHP

$to = $_POST["email"];
$subject = "SUBJECT";
$body = "Dear " . $_POST["fname"] . "," . "\r\n" . "\r\n" . "Thank you for...";
$headers = 'From: No-Reply@MYDOMAIN.com' . "\r\n" . 'X-Mailer: PHP/' . phpversion();

mail($to, $subject, $body, $headers);

    // First we set up some parameters for the receiver
    $receiver_name = 'ME';
    $receiver_email = 'corp@MYDOMAIN.com';
    $mydomain = 'MYDOMAIN';

    // This is for the sender's name - NAME OF THE SENDER
    $send_from = $_POST["fname"]. ' ' .$_POST["lname"];

    // This is for the sender's email - EMAIL ADDRESS OF THE SENDER
    $send_from_email = $_POST["email"];

    // This is for the message phone - PHONE NUMBER
    $send_phone = $_POST["phone"];

	//This gives the receiver the SENDER'S NAME and EMAIL ADDRESS	
	$send_header = 'From: ' . $_POST["email"] . "\r\n" . 'Reply-To: ' . 
             $_POST["email"] . "\r\n" . 'X-Mailer: PHP/' . phpversion();
	
	//This gives a sentence requirement if the sender wants the Sequence Builder
	if ($_POST["language"] == "on") {
	
	if ($_POST["prestore"] == "none") {
	$Sentences = "Sentences Requested: " . "\r\n" . "\r\n" . 
             $_POST["S1"] . "\r\n" . $_POST["S2"] . "\r\n" . $_POST["S3"] . 
             "\r\n" . $_POST["S4"] . "\r\n" . $_POST["S5"] . "\r\n" . $_POST["S6"]; }
	else {
		$Sentences = "Sentences Requested: Prestored from US"; }
	
									}
	
	else { $Sentences = ""; }
									 
	$send_title = 'EMAIL FROM: ' . $_POST["fname"] . ' ' .$_POST["lname"];
    $send_body = 'Sender: ' . $send_from . "\r\n" . "\r\n" . 
    'Email: ' . $send_from_email . "\r\n" . "\r\n" . 'Phone: ' . 
    $send_phone . "\r\n" . "\r\n" . 'Operating System: ' . 
    $system . "\r\n" . "\r\n" . 'Access Version: ' . 
    $version . "\r\n" . "\r\n" . 'REQUESTD: ' . 
    $requested . "\r\n" . "\r\n" . $Sentences . 
    "\r\n" . "\r\n" . "\r\n" . "\r\n" . 
    "The following message was sent to: " . 
    $_POST["email"] . "\r\n" . "\r\n" . $body;

    // Now we need to send the message
    $deliver = mail($receiver_email, $send_title, $send_body, $send_header);

   // the PHP mail() function return true if the message was processed so we check.
    if ($deliver == TRUE){ 
		$redirect = "yes";
	} else {
		$redirect = "no";
	}

	// This code will record the order submission in the orders LOG file
	$path = "Logs/REQS.txt";
	
        $s_name = $_POST["fname"] . " " . $_POST["lname"];
		$s_email = $_POST["email"];
		$s_date = date(DATE_COOKIE);
		$Content = $s_name . "|" . $_SERVER['REMOTE_HOST'] . "|" . 
                          $s_date . "|" . $s_email . "  ";

        $fh = @fopen($path,"a");
               fputs($fh,$Content . "\r\n");
        	   fclose ($fh);
	if ($redirect == "yes") {
		header("Location: http://www.MYDOMAIN.com/SUBMISSION.php");
	} else {
		echo '<p>We had a problem sending your request.
             Please e-mail your message directly to us at: ME@MYDOMAIN.com 
             <input name="button" type="button" id="button" 
             onclick=javascript:MM_goToURL("parent","index.php");
             return document.MM_returnValue value="Home" />';
    }

}

?>