I have postfix 2.x on Debian 8 setup. I modified main.cf to have
smtp_sender_restrictions = permit_mynetworks, reject_non_fqdn_sender, reject_unknown_sender_domain, permit
As of now, for a domain example.com, I can't send mail as firstname.lastname@example.org but I can send mail as email@example.com.
How can I restrict users from sending mail as someone else? I don't want
bob to act as