I've got ZCS 6.0.13_GA_2918 setup as a primary mail system, with an additional backup server (not running Zimbra) defined by an MX record.
The secondary MTA (postfix) has spamassassin and other filtering setup and relays to the Zimbra server.
Unfortunately, mail that the secondary MTA marks as spam is not considered spam by Zimbra.
I've got the secondary MTA in "trusted_networks" and "internal_networks" in salocal.cf.in.
Any insight on how I can go about telling the Zimbra server that mail marked as spam by the other MTA *is* spam, and to trust its headers (e.g. X-Spam-Flag)?
Thanks in advance.