> I'm honestly hoping there was a way to dynamically rewrite IP address in
> the email header to reflect the server it's being sent from. That would
> solve the issue completely.
Your Exim writes the Received: header that reflects the client IP
address here, so for authenticated SMTP submission you could simply
either omit that header or alter it to omit the IP address. This is
done by setting received_header_text to something with a conditional in
it and appropriate header values for each side of the conditional. The
information that would normally be in the Received: header you'd add can
be recovered from logs if you need it for some reason (eg to track down
abuse).
Locally we do something similar to this. Our inbound email is checked
by a commercial anti-spam system that we talk to using SMTP, but we
deliberately omit the hop through it from our Received headers because
we consider the use of SMTP for this to be just an implementation
detail.
- cks
