Thank you Bill once more for your reply.
I understand your point, but what I mean is a bit different. Functionality is full, no problem there.
case 1. When a user A forwards manually a mail he got from B to a user C, than C gets a mail from: A. This is forwarding. C replies to A
case 2. When a user A redirects manually a mail he got from B to a user C, than C gets a mail from: B. This is redirecting. C replies to B
This is not my own terminology, in Zimbra web client you may manually forward or redirect a message, exactly like the above examples, and these are the words used: forward and redirect.
However, when in filters, the only possibility there is, is to redirect (case 2). What I am looking for, is for functionality in filters to forward (case 1). It's not that it's there and not functioning. It's not there at all... And the available actions for filter are:
# zmmailbox help filter
notify "address" "subject-template" "body-template" ["max-body-size(bytes)"]