Is it possible to set a global mail filter in Zimbra, or even in Postfix if I have to. We are getting ready for the transition, and have an external mail appliance, I'd like to have it add a x-header and have zimbra put that in the junk folder. I'm not running anti-spam/virus services on the zimbra server. What determines by default what goes into the Junk box anyway?
Edit: Through further searching I found zimbraSpamHeader and zimbraSpamHeaderTag which will do exactly what I was looking for.