Some of my customers implemented commercial software that violate email-RFCs such that we have had to relax our header checks. In consequence, we receive more spam.
- I know the domains (customer.com) and IP-addresses (a.b.c.d/C) these emails come from
Kind request for help:
- Is it possible to setup one Postfix (2.11) instance on Linux such that:
- It applies only some header checks for emails from .*@customer.com
- But applies all header checks for all other email sources?
I thought of a combination of mynetworks that includes the subnet a.b.c.d/C in smtpd_recipient_restrictions -- allowing all these messages through -- and simultaneously avoid an open-relay with smtpd_relay_restrictions.
However, this has not worked out as expected.
Any idea or help is highly appreciated.
Thanks in advance.
For the current issue, I solved the problem by prepending REDIRECTs to header_checks as follows:
/^received: from.*customer.com.*by mail.own.com.*for.*luke@own.*/ REDIRECT email@example.com
This works so far as neeeded.
Irrespective thereof, I am still looking for a postfix configuration that would turn this text-based setting into an IP-Address-Range based forwarding rule....