I have a question about mail flow in Exchange 2010 environment. First, some background of our setup:
-we have two Exchange 2010 servers, one in production site, one in DR site.
-both of them are CAS role, mailbox role, and hub transport role at the same time
-they are in 1 DAG group
-we use a DNS alias as a CAS name and resolve it to the IP of the exchange server in production site (in a case of production server failure, we have to update the IP of DNS manually to point it to the DR Exchange)
-we have another hardware appliance as "send connectors"
-we use Outlook 2010
-users are connecting to production exchange server via the DNS CAS name
Now, my question is - when i checked the message tracking, i found that for each email submitted, it went to the DR exchange. In the message tracking log, the "ClientHostname" is always the production exchange server, and the "ServerHostname" is always the DR exchange server name. I don't understand why the email wasn't sent from production exchange directly to the send connector, but to the DR exchange first.
I hope im making myself clear here. Apologize that im not an Exchange expert, hopefully i've included all necessary information in the question.