How to control outgoing mail?

Question

Mail server

Hello. It is necessary to configure duplication of outgoing mail to the manager's address. Managers are not stupid, they know how to set up email clients so that there are no traces. These traces need to be fixed somewhere. Work on the IMAP protocol. Corporate mail on mass hosting [email protected]

Answer 1

you have a mailbox like [email protected] (corporate), right? like, [email protected]? Or is your domain screwed up, like traffic rules from Yandex?
managers connect it, or connect their boxes and send them from them?

Answer 2

This is a server task, you need to redesign, start your own mail server, enable logging.
You can make it easier, close the 25th port inside your network to everything except your SMTP relay, which will log everything. True, you can have a problem with SPF trust ...