We're running Postfix 2.3.3 on CentOS 5.4 for our SMTP service. Fairly standard setup with about 450 users. We're using a standard /etc/aliases file with includes to create various dynamically-generate aliases, including an "all staff" email address.
Management would like use of certain of these aliases to be limited to authorized senders and other aliases to be open to all. Is there an option to set up ACLs for individual aliases such that only certain senders are successfully delivered to those aliases?
I have no problem with it being accepted and a rejection message being sent. The folks doing the CC to the entire universe don't understand how 'Reply All' works anyway and as much as 10 years of reminders hasn't gotten through to them.
You can use the smtpd_restriction_classes setting in main.cf to specify a map of allowed senders. Check out this page: http://www.postfix.org/RESTRICTION_CLASS_README.html