If i have understand right Zimbra don't request mta/smtp user authentication when you send emails via smtp with a client in local network with Zimbra.
es. zimbra server stmp ip 10.10.0.3
email client ip 10.0.0.2
Is this right?
How can i force mta/stmp to authenticate a client in local network? I have seen that if you use a fake user with a fake domain you can however send emails... why?