- This will show how you can modify postfix to restrict who can send to certain addresses in your domain such as distribution lists like email@example.com
- These changes will most likely not persist between upgrades! (UPDATE: Just updated to 4.0.4 and the only thing that was wiped out was the change to /opt/zimbra/conf/postfix_recipient_restrictions.cf. Also, permissions on files created in /opt/zimbra/postfix/conf got changed.)
- This method can be spoofed by forging the MAIL FROM: header (so mail appears to originate from within the domain), so it isn’t foolproof, but it works for basic needs.