How can I Forward all email that is NOT [spam] filtered?

[richardteachout]

Does anyone know a way to configure postfix (I assume this is where I would have to make the change) so that email tagged as spam doesn't get forwarded remotely, but instead gets delivered to the mailbox (to the Junk Folder), but if it doesn't have a spam tag (I use [Spam] in the subject) then go ahead and follow the forwarding rules and allow off-site forwarding.


Basically:
Email Arrives
--> Spam Filtering Occurs
----- If Passed as OK, allow fowarding to remote email
----- If Flagged as spam, do not forward, deliver to Junk Folder

Ideally:
Email Arrives
--> Spam Filtering Occurs
----- If Passed as OK, Send to a more complex filtering system
----- If still Passes, allow fowarding to remote email
----- If Flagged as spam or does not pass send filtering system, do not forward, deliver to Junk Folder


Any ideas?

[uxbod]

Hmmm, what do you mean by more complex filtering system eg. additional SA installation with more RBLs, image recognition etc ? and if the email then passes feed it back into Zimbra ?

[richardteachout]

Yes.. the complex filtering might do exactly that.. say, run another few RBL's or something, and if it sees it as spam, then feed it back to zimbra.
(The second complex filtering would be nice, but not necessarily the primary goal.. the goal is to prevent messages marked as spam from leaving our network in an automatically forwarded fashion)

Basically, due to the HUGE amount of email being utilized in our Zimbra system, we want to prevent users from forwarding their "spam" email to an outside email account (aol.com for example) as aol see's the spam, and flags our servers as the spammer (since we sent it to them). Currently we had to disable the ability to forward any email, but unfortunately that is a pain for some of our customers... therefor, it would be nice to be able to allow them to forward their email, but only email Zimbra does not see as "Spam".

Does that clarify this a bit more?

[Rich Graves]

A labor-intensive way to do this might be to disable forwarding in class of service, and accomplish forwarding by having users (or perhaps a user-friendly-ish web page under your control) create a filter rule. Filter rules run post-spam filtering... I think? (Untested!!!)