Claus Assmann <ca+postfix-us...@esmtp.org> wrote: >> With SMTP there is no per-recipiet end-of-data reply, and a >> reject reply will block mail for all recipients. > > AFAICT PRDR can do that -- it's implemented in exim and some other MTA. > However, it's barely used...
One way to "encourage" its implementation would be to reject connections from "dubious" reputation hosts unless PRDR (Per-Recipient Data Responses) is negotiated/requested. -- A. Filip
