title: Handling undelivered emails in webapp
body: <p>We have a typical business web app that allows our users to send e-mails with offerings to their clients. We set user e-mail in FROM field so the client can reply directly to the user. The problem is that because of SMTP protocol, undelivered e-mail notification is returned to our e-mail address(the address of the account we send e-mails from). </p>
  
  <p>Do you know elegant way to handle this undelivered emails? I mean the easiest way to let the sender know that his mail was not delivered.</p>