We need to have bounce handling installed for our CiviCRM 3.3 on Drupal 6 installation.
We can provide an E-Mail Address which can be used for bounce handling, accessible through IMAP.
Bounced E-Mails should allow CiviCRM to set users on hold, according to it's own specifications http://wiki.civicrm.org/confluence/display/CRMDOC33/Bounce+Handling. so that new mailings will not be send to users which are "on hold".
Additionally we need the ability to autofill E-Mails according to http://wiki.civicrm.org/confluence/display/CRMDOC33/Autofiling+email+activities+via+EmailProcessor
E-Mails send there need to be associated with the civicrm users as activities in the from, to, cc and /or bcc accounts.