We need to accept email from a server that sends out using a non-existing domain. That server is not under my control.
In my main.cf I have
smtpd_client_restrictions = permit_mynetworks, hash:/etc/postfix/access, permit_sasl_authenticated
in /etc/postfix/access I have
<server's ip> OK vps1.nonexistingdomain.com OK
However, when I recieve messages from that server in my logs I see:
Jul 26 10:30:07 mail3 postfix/smtpd: NOQUEUE: reject: RCPT from vps1.nonexistingdomain.com[ip address]: 554 5.1.8 <email@example.com>: Sender address rejected: Domain not found; from=<firstname.lastname@example.org> to=<email@example.com> proto=ESMTP helo=<vps1.nonexistingdomain.com>
As another workaround I tried to manually hardcode this hostname:ip into my /etc/hosts, but that makes no difference.