Exchange 2007 server rols overview.
- Client Access:
The Client Access server role supports Microsoft Outlook Web Access, Microsoft Exchange ActiveSync client applications, Post Office Protocol version 3 (POP3) and Internet Message Access Protocol version 4 (IMAP4) protocols.The Client Access server role accepts connections to your Exchange 2007 server from different clients.
Clients such as Microsoft Outlook (also the Express version) and Eudora.
Hardware clients, such as mobile devices, use ActiveSync, POP3, or IMAP4 to communicate with the Exchange server. This role, the Client Access server role is required in every Exchange Server 2007 organization.
- Edge Transport:
The Edge Transport server role is used in the perimeter network (DMZ) as a stand-alone server or as a member server of a perimeter-based Active Directory domain. The Edge Transport server handles all Internet-facing mail flow, which provides Simple Mail Transfer Protocol (SMTP) relay and smart host services for the Exchange organization.The server that has the Edge Transport server role installed doesn’t have access to the Active Directory directory service. All configuration and recipient information is stored in the Active Directory Application Mode (ADAM) directory service.
To perform recipient lookup tasks, the Edge Transport server requires data that resides in Active Directory.
EdgeSync is a collection of processes that are run on a server that has the Hub Transport server role installed to establish one-way replication of recipient and configuration information from Active Directory to the ADAM instance on an Edge Transport server.
The Microsoft Exchange EdgeSync service copies only the information that is required for the Edge Transport server to perform anti-spam configuration tasks and the information about the connector configuration that is required to enable end-to-end mail flow.
- Hub Transport:
The Hub Transport Role will be deployed in your Active Directory directory service forest, the Hub Transport server role handles all mail flow inside the organization, applies transport rules, applies journaling policies, and delivers messages to a recipient’s mailbox. Messages that are sent to the Internet are relayed by the Hub Transport server to the Edge Transport server role that is deployed in the perimeter network. Messages that are received from the Internet are processed by the Edge Transport server before they are relayed to the Hub Transport server.
If you do not have an Edge Transport server, you can configure the Hub Transport server to relay Internet messages directly. You can also install and configure the Edge Transport server agents on the Hub Transport server to provide anti-spam and antivirus protection inside the organization.
The Mailbox server role hosts the mailbox databases, which contain users’ mailboxes. If you plan to host user mailboxes, public folders, or both, the Mailbox server role is required.
In Exchange Server 2007, the Mailbox server role integrates with the Active Directory directory service better than the mailbox features and functionality in earlier versions of Exchange. The Mailbox server role also improves the information worker experience by providing richer calendaring functionality, resource management, and offline address book downloads.
- Unified Messaging:
Exchange Server 2007 Unified Messaging combines voice messaging, fax, and e-mail into one Inbox, which can be accessed from the telephone and the computer. Unified Messaging integrates Exchange Server 2007 with the telephony network in your organization and brings the features found in Unified Messaging to the core of the Exchange Server product line.