On my companies mail server there is a mail address firstname.lastname@example.org which sends a mail to every user which is useful for internal communication etc. I want to restrict this recipient to only allow mails from our mail server and reject any mail from outside to this address. What is the best way to do this in postfix?
I found a pretty simple solution: Use postfwd (postfix firewall daemon).
Create a rule:
sender_domain!=example.org ; email@example.com ; action=REJECT firstname.lastname@example.org only allowed for example.org addresses