[pmg-devel] [RFC pmg-api 4/4] add support for before queue filtering

[Dietmar Maurer]

> We can only reply with 554 (permfail) if all recepients are blocked.
> In the case that some accept the mail, we reply with 250 OK and generate bounces
> for all blocking recepients by default. (This is also the behavior that postfix
> has when not enabling receiver verification and the downstream server rejects
> recepients).
> 

IMHO this is the wrong approach. We must never sent NDR with this setup.