I have a user with an IPhone that needs to be able to send and receive email through our Exchange Server. He is currently setup using IMAP4 and can receive email but is not able to send to anyone outside the domain unless SMTP Relay is turned on in the Exchange server. The problem is that once authentication is added to the SMTP relay, all incoming email shows as "Rejected" in the Barracuda with the error "454 5.7.3 Client does not have permission to submit to this server." We are using a Barracuda Spam Firewall 300. Anyone know how to fix this.