Because organizations tend to group their management tasks around a core set of server roles, Exchange 2010 maps Exchange Server management to this same approach.
A server role is a unit that logically groups the required features and components needed to perform a specific function in the messaging environment. The requirement of a server role is that it is a server that could be run as an atomic unit of scalability. A server role is composed of a group of features.
Server roles, the primary unit of deployment, enable administrators to easily choose which features are installed on an Exchange server. Logically grouping features in server roles offers the following advantages:
- Reduces attack surface on an Exchange server.
- Allows you to install and configure an Exchange server the way you intend to use it.
- Offers the ability to fully customize a server to support your business goals and needs.
The following figure illustrates a domain with each server role deployed.
Exchange 2010 includes the following server roles:
- Mailbox Server This server hosts mailboxes and public folders. For more information about the Exchange 2010 Mailbox server role, see Overview of the Mailbox Server Role.
- Client Access Server This is the server that hosts the client protocols, such as Post Office Protocol 3 (POP3), Internet Message Access Protocol 4 (IMAP4), Secure Hypertext Transfer Protocol (HTTPS), Outlook Anywhere, Availability service, and Autodiscover service. The Client Access Server also hosts Web services. For more information about the Exchange 2010 Client Access server role, see Client Access.
- Unified Messaging Server This is the server that connects a Private Branch eXchange (PBX) system to Exchange 2010. For more information about the Exchange 2010 Unified Messaging server role, see Unified Messaging.
- Hub Transport Server This is the mail routing server that routes mail within the Exchange organization. For more information about the Exchange 2010 Hub Transport server role, see Transport and Overview of the Hub Transport Server Role.
- Edge Transport Server This is the mail routing server that typically sits at the perimeter of the topology and routes mail in to and out of the Exchange organization. For more information about the Exchange 2010 Edge Transport server role, see Transport and Overview of the Edge Transport Server Role.