> On Jan 27, 2021, at 9:40 PM, Andy Smith <[email protected]> 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...
--
Viktor.
