I have a postfix instance dedicated to being the main MX (IN).
I normally use other postfix instances for sending emails out (OUT).
Of course, even this "IN" instance needs to send emails out, mainly bounces.
Now I am also implementing forwarding rules: "if you receive an email
destined to this address, than forward it out to this other email address".
Other addresses are @gmail.com, @msn.com, etc...
In order to do that "right" I also implemented an SRS service, so to have
my domain as the envelope sending address.
Now I also want to enable DKIM-signing of these outgoing emails.
- SRS (or at least the product I am using, postsrsd) works at the "cleanup"
level, so after smtpd
- My DKIM-signing tool is a milter, so acts at smtpd time. So the email it
sees is with the original sending domain and not my domain.
How can I achieve the intended behaviour?
Thank you in advance for your help