We've recently migrated a client to Exchange 2010 from 2003. We are using outlook 2003 clients on floor. Just got word that the OOF not flowing to external recipients (even when configured via OWA). I have selected the option within OWA to send out of office replies to internal and external recipients. I have checked my spam gateway (which is have a send connector via exchange) and there is nothing there. It's as if exchange isn't even sending the message at all. Message tracking only shows out of office replies being sent/generated for internal domain users.