I have a mix of Exchange 2003 and Exchange 2010 in my mail organization. About mid morning today, all emails to the 11 recipients on the only Exchange 2010 server stopped receiving messages send from outside sources, but still receive messages sent from inside the organization (whether on the Exchange 2010 or 2003 server). I am home sick today with a fever, and I simply cannot think clearly enough to address this. Any and all help in troubleshooting why this is happening would be appreciated.
Current scenario for mailflow:
All incoming mail comes to a front end 2003 server. It routes mail to the appropriate back end server (2003 or 2010).