I have recently integrated a Barracuda with Exchange 2003 SP2 by way of MX record intercept, however I believe some creative genius seems to bypass the Barracuda and is still accessing the mail server. Both the Barracuda and Exchange 2003 are behind the same PIX. All MX references have been changed to the Barracuda, but mail.emailserver.com still point to the Exchange server.
Currently the Exchange server config is as follows:
Route of mail from the world: Internet -> Barracuda -> Mail Server -> Email client [ex. Outlook]
Route of email to the world : Email client [ex. Outlook] -> Mail Server -> Barracuda -> Internet
(Mail Server -> Barracuda by way of a Smart Host forward on the Internet Mail SMTP Connector)
Email server is NOT an open relay.
Required authentication for incoming and outgoing on all email clients.
I would like to force the Exchange server to take incoming mail only from the Barracuda and allow an authenticated Email client [ex. Outlook] to Send/Receive mail to the Exchange Server directly.