Hi, we have many AD sites with DCs onnly. We plan to deploy an exchange infrastructure in the head quarter and where asking ourselves : will remote sites users be able to connect to their mailboxes that are hosted in the head quarter ? MS Documentation state that a CAS must be deployed in each site in which an MBX server is deployed. But what about sites where there is no MBX Server ? Thanks

Hello, you do not need CAS server where you do not plan to deploy mailbox servers, you can have the mailbox for the user located in head quarter and they will be able to access using the CAS server in the same site as the MBX Server however there may be client performance issues depending on bandwidth available between the user location and head quarters . you might want to enforce cached mode on all clients Dhruv

Hi, I was suspecting that this would work as nothing was stating that this will not work. Have you any reference regarding this ? Thanks

Sites allow services to locate resources close to them. They have nothing to do with how a user makes a connection to an application like Exchange. To my knowledge, there is no documentation that states this directly.