title: Python smtpd: full debug mode
body: <p>I want to run a fake SMTP server on my raspberry PI (rpi). I found a good fake server that I usually start with the following command:</p>
  
  <pre><code>sudo python -m smtpd -n -c DebuggingServer 0.0.0.0:25
  </code></pre>
  
  <p>I can easily send e-mail with a python client or telnet commands from the localhost and foreign computer (Linux, Windows). However, the scan2mail function of an older HP printer causes serious issues because it simply reports me an error: The e-mail could not be sent, try again later.</p>
  
  <p>Is there a way that Pythons <code>smtpd</code> shows me every byte it receives? (So that I can track down the HP scan2mail issue.)</p>
  
  <p>Pls let me know if you need more infos.</p>