We have a Power7i (V7R1) and an Exchange 2007 setup. For all the other devices and appsin our network that can send status reports via e-mail, we just point them to the server runningthe Exchange Hub Transport role, provide a return address (auto_mail@domain.com or password@domain.com) and a recipient, and the mail goes through the Exchange Server system just fine to the recipient's mailbox.
However, for SMTP email originating on the Power7i, it looks like it is bypassing our in-house Exchange SMTP (which is configured to accept SMTP traffic from any IP on our subnet) and using the MX records on the public DNS, because the messages are going through our Symantec Spam Filter subscribed service at MessageLabs (we previously saw them going through MXLogic before we changed spam filters).
We've looked and looked at the mail settings on the...