title: PHP mail issue with www-data
body: <p>I am trying to invoke sendmail via PHP's mail function by the following code:</p>
  
  <pre><code>$to      = 'blah@email.state.edu';
      $subject = 'test';
      $message = 'test';
      $headers = 'From: mail@smartrek.blah.me' . "\r\n" .
                 'Reply-To: mail@smartrek.blah.me' . "\r\n" .
                  'X-Mailer: PHP/' . phpversion();
  mail($to, $subject, $message, $headers);
  </code></pre>
  
  <p>However in my mail.log I am getting a message that the from is not the address I specified in the header:</p>
  
  <pre><code>&lt;www-data@Name&gt;: Sender address rejected: Domain not found
  </code></pre>
  
  <p>Why is this?? I am running PHP's fast-cgi on ubuntu
  Why doesn't sendmail use the header that I have specified via the PHP code?</p>