Howdy, Been scratching my head on this one for a while.
First off, running Exchange 2010 Sp3 RU5 across the board.
I have attached a diagram of our environment for visual aid. Please take a look as it makes more sense.
I have drawn the correct mail flow in black and what is happening in red.
Forest A Site A, has a dedicated edge, dedicated Hub and dedicated CAS
Forest A Site A child domain 1, has a multi-roled MBX,HUB,CAS
Forest A Site B child domain 2, has a multi-roled MBX,HUB,CAS
Forest B Site C, has a multi-roled MBX,HUB,CAS
Mail flows TO child domain 2 just fine, but outgoing mail from that same domain keeps routing through HUB in child domain 1 instead of HUB in forest root domain.
The send connector for the organization in Forest A is configured to only send through the dedicated HUB server in Forest A. The Receive connector in Forest A's HUB is also configured correctly. But no matter what i do, mail outgoing from child domain 2 continues to flow to child domain 1 instead of through the dedicated HUB server.
Mail needs to flow so for now i added the HUB in child domain 1 as a source server in the organization's send connector and set up the receive connector in child domain 1 to allow a work around for now.
I think this is an issue in the routing group connector but its just a guess. Any ideas?