title: What is the behavior difference between return-path, reply-to and from?
body: <p>On our mailing application we are sending emails with the following header:</p>
  <pre><code>FROM: marketing@customer.com
  TO: subscriber1@domain1.example
  Return-PATH: bouncemgmt@ourcompany.example
  </code></pre>
  <p>The problem that we are facing is that some email servers will bounce back a message immediately and use the from or reverse path (<code>marketing@customer.example</code>) instead to our bounce mgmt server. We want to know if we modify in the header the reply-to to be the same as the return-path if we will be able to catch all bounces.</p>
  <p>Any other ideas are welcome?</p>
  <p>We are using the following documents as references:
  <a href="http://en.wikipedia.org/wiki/Variable_envelope_return_path" rel="nofollow noreferrer">VERP</a>
  <a href="http://james.apache.org/server/rfclist/smtp/rfc0821.txt" rel="nofollow noreferrer">RFC</a>
  <a href="http://en.wikipedia.org/wiki/Bounce_message" rel="nofollow noreferrer">Bounce Messages</a></p>
  <p><a href="http://scriptolog.blogspot.com/2007/08/smtp-log-parsing.html" rel="nofollow noreferrer">SMTP Log Parsing to get Bounces</a></p>
  <p>EDIT 1: A few more bits of information to see if we can get this resolve.</p>
  <p>We want to know at what point the email server relaying the message will choose to use the reply-to versus the return-path. We have notice that when the first SMTP server relaying the message gets rejected it sends it to the reply-to, but when it happens after one hop it sends it to the return-path.</p>