Zentyal 3.0 updated: gmail smtp Sending Spam on my behalf

[jmituzas]

As I have posted yesterday here in the wrong place (desktop) 

figured I could at least back link from here http://forum.zentyal.org/index.php/topic,15284.0.html

Anyways I know that this is a bit hard to troubleshoot  , this was my first attempt at Zentyal for mail relay utilizing gmail for SMTP.

Looks like I will be trying this all again  this evening but how can I protect myself from this happening again? I don't need something sending out emails on my behalf.

[jmituzas]

All I can find is this  will try and see if it helps
http://www.postfix.org/BACKSCATTER_README.html

[jmituzas]

Never mind that 

The instructions here tell the person receiving all these backscatters, specifically email_feedback_handler@mta-inbound.cluster3.convio.net how to deal with it.

If the emails were sent by random mail deamons all around the internet to your address, then this would help me out.