Rafael Azevedo - IAGENTE:
>
>
> > Configurable, perhaps. But it would a mistake to make this the
> > default strategy.
> >
> > That would make Postfix vulnerable to a trivial denial of service
> > attack where one bad recipient can block all mail for all other
> > recipients at that same site.
>
> Not if it could me parametrized. As I said, what if we get 100
> errors in sequence?
Big deal. Now I can block all mail for gmail.com by getting 100
email messages into your queue.
I could add an option to treat this in the same manner as "failure
to connect" errors (i.e. temporarily skip all further delivery to
this site). However, this must not be the default strategy, because
this would hurt the far majority of Postfix sites which is not a
bulk email sender.
Currently, Postfix error processing distinguishes between (hard
versus soft) errors, and between errors (during versus after) the
initial protocol handshake. I don't have time to develop more
detailed error processing strategies, especially not since this is
of no benefit to the majority of the installed base.
Wietse
