On 8/27/2020 3:26 PM, Gregory Heytings wrote:
For cases like the one you have in mind, it is necessary to use a
milter.
Thank you for saving me some head scratching. It wouldn't be the
end of the world to spin up an Exim VM (its system_filtering is
capable of this black magic), but would prefer staying in Postfix.
Do you have a milter in mind for this task?
MIMEDefang could do it: a few lines of Perl in the filter() callback.
Yes, that would be the standard milter to do what you want. But if I
were you I would ask myself if what you'd like to do is really
necessary, and worth the price of maintaining a specific tool for it.
Note also that, if you control more than Postfix, it might be possible
to do what you want outside of Postfix. For example, if you have a
Dovecot server behind your Postfix, you could do what you want with
Sieve filters.
Gregory
My Postfix is managed by Proxmox, they have a filtering solution built
into Proxmox Mail Gateway that will allow me to copy the recipient
address to the subject line, it's not precisely what I wanted, but we
are getting close.
Thanks everyone for your help!
