Wietse Venema:
> Jose Borges Ferreira:
> > On Wed, Dec 3, 2014 at 1:51 PM, Wietse Venema <wie...@porcupine.org> wrote:
> > > Jose Borges Ferreira:
> > >> This is the scenario.
> > >> Box 1 : just receive email from "outside" - inbound flow.
> > >> Box 2 : used to sent email to the "outside" - oubound flow.
> > >
> > > Inbound MTA: primary MX for your domain(s). If mail can't be
> > > delivered, use Postfix's relayhost feature to deliver outbound mail
> > > via the outbound MTA, if you can't use standard MX logic to deliver
> > > directly to the sender's MX hosts.
> >
> > That's my initially idea, but was afraid that relayhost would "catch"
> > more than intended.
>
> It catches outbound mail. Postfix cannot generate other mail, as
> long as all mail from inside has an inside envelope sender address.
And all mail from outside has an outside envelope sender address.
> And that is standard firewall hygiene.
Wietse
