Your company has four offices. Each office is configured as an Active Directory site.
You have an Exchange Server 2013 organization that contains nine servers. The servers are configured as
shown in the following table.
A user named User1 is in a distribution group named D_Sales. The mailbox of User1 is in a database that is
active on MBX4 and is configured to use MBX5 as an expansion server.
You need to ensure that email sent to D_Sales from the Internet is received by CAS1, and then routed from
MBX1 to MBX4.
What should you do?
A.
Configure Site1 as a hub site.
B.
Modify the expansion server setting of D_Sales.
C.
Modify the SubmissionServerOverrideList list on MBX1.
D.
Configure Site3 as a hub site.
Explanation:
As the messages are routed from sender Mailbox Server Transport Service to recipient Mailbox Server
Transport Service, I would say that it makes sense for the Expansion Server settings for the DL to be amended
to MBX4.
This action would remove MBX5 from the equation, and as the expansion server setting serves as the routing
destination when specified, this would also ensure the emails are routed from MBX1 to MBX4.
Assuming that all external email is received by CAS1 in Site1, then MBX1 would be responsible for routing the
email, via the transport service to the other mailbox servers at other sites.
When a hub site is used, all email traffic from the sites configured to use the hub site is affected.
The question states that email sent to D_Sales needs to be rerouted, not all traffic.
There is no mention of the need for hub sites, AD site costs, or other sites with internet facing CAS servers.
http://technet.microsoft.com/en-us/library/jj916681(v=exchg.150).aspx
Exchange 2013 Mail Flow
http://technet.microsoft.com/en-us/library/aa998825(v=exchg.150).aspx#RoutingDest