I am sure this has been done but after about 2 days of wasted time researching, I'm just not getting what I need.
What's happening is that we are using Google Apps for our email (MX servers are pointed to GApps) and then I am downloading each user's mailbox (email@example.com as hosted on GApps) through POP3 connector on SBS 2008 Exchange. I can send email to other domains just fine through our ISP's smart host.
My problem is this: I have setup a user account on SBS for User1 (firstname.lastname@example.org) and therefore she has a local mailbox on Exchange. I don't have a user account for Mr. President (email@example.com) as he wants to continue using IMAP of GApps for his Mac. User1 cannot send any emails to President. But User1 can send emails to any other user with an account on SBS 2008.
I have tried setting the Hub Transport Accepted domain for domain.net to "Internal Relay" while domain.local is set to "Authoritative" and as the default accepted domain.
Exchange gives me this error: The recipient's e-mail address was not found in the recipient's e-mail system. Microsoft Exchange will not try to redeliver this message for you. Please check the e-mail address and try resending this message, or provide the following diagnostic text to your system administrator.
550 5.1.1 RESOLVER.ADR.RecipNotFound; not found
Any ideas as to what this problem is? I would prefer that even mail sent to User1@domain.net be sent through the smart host and then get received by GApps and then get pulled through POP3 for Exchange...
I understand that what I want possibly negates Exchange's purpose and increases bandwidth requirements, but my business case for this is IF exchange were to fail, we will have ALL our inbox intact on Google Apps. And of course, if there were a virus sent from one of our workstations, it would be better if it passes through Google Apps first before it gets to Exchange (whereas in the default configuration, it just sends it directly to the Exchange mailbox and never goes through the internet).