Working on I found another problem. We receive email with and envelope sender address from our domain but coming from another smtp.
Incoming MTA stage: 2013-06-28 18:34:55 1UsbdP-0004vw-5o <= info@mydomain.ext H=relayout03-redir.dns-servicios.com [82.194.80.185] P=esmtp S=2008 id=20130628163447.32314.qmail@vlc-212.dns-servicios.com
How can I check if an email from my domain comes from another smtp and quarantine via SA or reject?