satheesh.net

CatchAllAgent is an Exchange 2007 Transport Protocol Agent. If a message comes in, and a
recipient of that message does not exist (unknown recipient), the recipient typically gets
rejected by the Recipient Filtering feature (which is also a Transport Protocol Agent).
The CatchAllAgent can be configured to rewrite the recipient address for unknown recipients
such that such messages end [...]

Microsoft has a very cool Exchange connectivity analyzer. It’s web-based and free!
You can use it for testing ActiveSync, Exchange Web Services, Outlook connectivity and e-mail tests. Give it a try and find out if your setup works as it should.