I'd like to ask if some of you has experience with configuring google apps and zimbra the latter being the main mail server (declared in MX records for our domain).
Since we have Education Edition, I've configured forwarding from Google Apps (G) to Zimbra (Z) (G -> Z) unfortunately if the reverse (Z -> G) forward is activated it would end in infinite loop (Z-> G -> Z -> G etc.).
The only feasible solution seems to create a [global] sieve filter checking email headers and discarding messages where appropriate.
Perhaps community has better ideas/solutions ?