I've been racking my brains on this, and thought I'd reach out to the community to check on how I can best accomplish this.
My soon-to-be-production architecture is Zimbra OSE 7.1.2:
2x proxy servers w/MTA, LDAP (master/replication), anti-virus/spam etc
2x mailstore servers
I've setup multi-domain with SSL certificates (multiple external->internal virtual IPs), and tested working for SMTP+IMAP w/TLS, and of course webmail in mixed mode (i.e. http redirects to https for login, then back to http for mail browser).
So far so good. If it was the good old days of the internet back in the 80s, I'd be in production already . However, SPAM is out there aplenty (unfortunately my domains do get a lot of SPAM), and that also affects the mail archiving portion of things.
I'm using mailarchiva in my existing cyrus+postfix setup, with MIMEdefang in milter mode such that milter=<inet:mimedefang> <inet:mailarchiva:, with tempfail.
Mailarchiva's default recommendation is to just stick inet:mailarchiva into the milter. However, if I do this, I know I'll end up archiving every single piece of mail, SPAM or otherwise (been there, archived close to 1M emails in 48 hours before the archiving server died; sigh). So from judicious browsing and searching on the forums and others, my options seem to be:
1) use ASSP as a border SPAM relay, in front of Zimbra
2) install amavisd-milter and configure the same way as my existing setup (but of course replacing mimedefang with amavisd-milter).
Can anybody advise which is the easiest (I'll qualify this in a tick) way to handle this situation?
By easiest, I don't mean just in implementation only, but also in maintenance and user experience, e.g. how easy is it to retrieve accidentally marked SPAM messages, how users can report SPAM or otherwise, whitelist/black domains, whilst still handling my multiple domains etc
Thanks in advance for any opinions/recommendations.