Mail delivery failed: returning message to sender - php

Question

I would like to add a failed message re-direct to my mail script, so that if a user enters a wrong address in the email field it gets returned to me, and not to my hosting company's inbox, how do I do that? I've already added return-path but doesn't work, what else can i do to get this code to work.
Here is the code:
<?php if(isset($_POST['submit'])) {
if(trim($_POST['first-name']) == '') {
$hasError = true;
} else {
$name = trim($_POST['first-name']);
}
//Check to make sure that the last name field is not empty
if(trim($_POST['last-name']) == '') {
$hasError = true;
} else {
$lname = trim($_POST['last-name']);
}
//Check to make sure sure that a valid email address is submitted
if(trim($_POST['email']) == '') {
$hasError = true;
} else if(!preg_match("/^[_\.0-9a-zA-Z-]+#([0-9a-zA-Z][0-9a-zA-Z-]+\.)+[a-zA-Z]{2,6}$/i", trim($_POST['email']))) {
$hasError = true;
} else {
$email = trim($_POST['email']);
}
//Check to make sure that the phone field is not empty
if(trim($_POST['tel']) == '') {
$hasError = true;
} else {
$phone = trim($_POST['tel']);
}
//Check to make sure that the phone field is not empty
if(trim($_POST['company']) == '') {
$hasError = true;
} else {
$company = trim($_POST['company']);
}
foreach (array($_POST['q1']) as $value) {
$q1 = $value[0];
$q2 = $value[1];
$q3 = $value[2];
}
//If there is no error, send the email
if(!isset($hasError)) {
$to = 'me#host.com';
$recipient = $email;
$subject = 'Subject';
$headers = "From: Me\n" . $to . "\r\n";
$headers .= "Reply-To: ". $to . "\r\n";
$headers .= "Return-Path: ". $to . "\r\n";
$headers .= "MIME-Version: 1.0\r\n";
$headers .= "Content-Type: text/html; charset=ISO-8859-1\r\n";
$msg1 = "First Message";
$msg2 = "Second Message";
//Send Email
mail($recipient, $subject, $msg2, $headers);
mail($to, $subject, $msg1, $headers);
$emailSent = true;
}
}
?>

Answer 1

the return path is set by the mta based on the envelope sender, you can't just set that in the headers yourself. You can try to set the envelope sender using the $additional_parameters argument of the mail function. See Example #3 on http://www.php.net/manual/en/function.mail.php
In your case, that would be something like
mail($recipient, $subject, $msg2, $headers, "-f $to");
On some systems overriding the envelope sender using -f is restricted. In that case you'd probably have to switch to submitting the mail via SMTP instead of calling the sendmail binary via mail().