Dominic Raferd:
> Checking my logs I see that some senders are trying to fake our domain
> and use our server to send mails to third parties masquerading as one
> of our own domains (without authenticating first).
>
> They are stopped by smtpd with response 'Relay access denied', but
> instead of 5xx permanent rejection smtpd gives 454 4.7.1 temporary
> rejection, which surely encourages them to keep trying. Why is this,
> and can I change it?
postconf -x smtpd_relay_restrictions
As a safety for sites migrating from Postfix 2.x, the default
is to defer instead of reject.
Wietse
