Probably a basic one but can figure it out.
I am setting up a Postfix server to accept mail form our LAN and relay it to external WAN.
Mail sent from the LAN devices (MFC etc) get this error:
Remote Server returned '554 5.7.1 Client host rejected: cannot find your hostname, [172.16.255.89]'
172.16.255.89 is indeed the correct LAN IP. How do I authorize it ?