With Exchange 2010 and Database Availability Group (DAG) failover of the database, the Client Access Server / Hub Transport Server design is a very different scenario since you don’t have to ...

There must be at least one Client Access Server role installed in every Active Directory site running a Mailbox server role in order for your Exchange 2007 environment to function.

Question: Our organization has Exchange 2007 deployed. We have a high availability solution consisting of 4 Exchange 2007 servers -- two servers that have the Hub Transport and Client Access server ...

Instead, a MAPI connection is terminated on a Client Access Server, which then proxies the connection back to the correct mailbox server that holds the database.

Here's a list of new features and related resources for those interested in testing Microsoft's next-generation Exchange Server 2013.