Viktor Dukhovni:
> > On Jan 27, 2021, at 9:40 PM, Andy Smith <a.sm...@ldex.co.uk> wrote:
> >
> > Correct, its a dynamic value. It can only be known by reading the reply-to
> > value from the headers of the same message.
>
> One way to do this entirely in Postfix is to:
>
> 1. Delete the evil "From:" header that matches the "www" user
> on input via header_checks.
> 2. In the same input cleanup(8) instance PREPEND an "X-Reply-From"
> header that is a copy of the "Reply-To" header (when present).
> 3. Use sender_dependent_default_transport to send mail from "www"
> to a custom smtp(8) delivery transport (new master.cf entry).
>
> In the custom smtp transport:
>
> 4. Use smtp_header_checks to rewrite "X-Reply-From:" to "From:"
>
> In the regular smtp transport:
>
> 5. Use the smtp_header_checks "IGNORE" action to drop the
> "X-Reply-From:" header.
>
> The only thing this does not do is modify the envelope sender
> address to match the value in the header. Doing that goes
> outside any built-in Postfix features that come to mind...
And fiding MAIL FROM is what they need to do most...
Wietse
