Rich Wales:
> > Postfix allows you to transform remote server responses into
> > arbitrary other responses. Thus, you can change a 5XX (hard reject) into
> > something else. . . . This feature is available in Postfix 2.7.
>
> I'm running 2.8.1, so that's potentially good news for me. Thanks.
>
> Assuming that I can use smtp_reply_filter to mark "block list" rejections
> in a distinctive manner (and prevent them from being treated as hard
> rejects), is there any way for me to convince Postfix to send these
> messages to an alternate smarthost?
The idea is to use
/etc/postfix/main.cf:
smtp_fallback_relay = smarthost.provider.example
smtp_reply_filter = ...your filter...
This sends all mail to the smarthost that fails with a 4xx SMTP
reply (whether due to your reply filter, or otherwise).
The smtp_fallback_relay feature also sends mail to the smarthost
when the destination can't be found. That's not what you need, but
that's because smtp_fallback_relay was implemented for a different
use case, there was not a whole lot of time for proper engineering,
and thus the behavior was hard-coded.
Wietse
