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The Five Server Roles of Exchange 2010

The Five Server Roles of Exchange 2010

Exchange 2010, with its five roles, benefits those who have a clear plan of what they want to achieve from their email servers.

Guy Thomas

Guy Thomas is a computer consultant and writer with attitude and a great sense of humor.

Guy Thomas is a computer consultant and writer with attitude and a great sense of humor.

Compared with Exchange 2003, one of the biggest changes in Microsoft's philosophy is that Exchange 2010 now has five server roles.  This passion for 'Roles' mirrors Microsoft's mantra of 'Customize This Server' on Windows Server 2008.

At one extreme you could deploy a single 2010 Server with four roles and forget about the Edge (Gateway) server role.  At the other extreme you could have five separate Exchange servers, one for each role.  Microsoft calls this increased scalability.  I think of it as greater flexibility.

Exchange 2010, with its five roles, will benefit those who have a clear plan of what they want to achieve from their email servers.  In retrospect it could be argued that Exchange 2003 tried to be all things to all people.  As a result, add-ons like Conference Server and Instant Messaging are not available; instead Exchange 2010 concentrates on being a premier email server.

In 2003 versions of Microsoft Exchange Server you could not select specific roles, because all features were installed on each server.  Exchange Server 2010 uses the concept of server roles to control which capabilities are installed on which Exchange server.  The benefit of this new arrangement is improved scalability, better security and simplified administration.

Note: Exchange Server 2010 should be installed on a member server and not a domain controller.

The five roles are:

  • Mailbox Role
  • Client Access (CAS)
  • Hub Transport (Bridgehead)
  • Unified Messaging
  • Edge Transport (Gateway)

Mailbox is a good name for the core Exchange server; it stores all the email.  Incidentally, remember to install IIS and the World Wide Web (WWW) service.  Installing a Mailbox Server on Windows Server 2008 and linking it a CAS (Client Access Server) would be like pairing the Back-end / Front-end servers in Exchange 2003. 

One surprise is that Mailbox servers do not transfer messages between mailboxes. For this message delivery you need a Hub Transport server.  Bear this in mind when troubleshooting non-delivery of internal email.  For smaller Exchange Organization you could combine the Mailbox and Hub Transport roles on the same server.

Conceptually, the Mailbox server must connect with the Active Directory, CAS, the Hub Transport server, Unified Messaging server and Microsoft Outlook clients.

Here is a list of Exchange related services on your Windows 2008 Server.

  • MSExchangeIS - Microsoft Exchange Information Store
  • MSExchangeADTopology - Microsoft Exchange Active Directory Topology
  • MSExchangeMailboxAssistants - Microsoft Exchange Mailbox Assistants
  • MSExchangeSearch - Microsoft Exchange Search Indexer
  • MSExchangeServiceHost - Microsoft Exchange Service Host
  • MSExchangeMonitoring - Microsoft Exchange Monitoring
  • MSExchangeSA Microsoft - Exchange System Attendant
  • MSExchangeMailSubmission - Microsoft Exchange Mail Submission
  • Msftesql-Exchange - Microsoft Search (Exchange Server)
  • MSExchangeTranportLogSearch - Microsoft Exchange Transport Log Search

Mailbox servers can also be used to host public folder databases, and produce address lists including offline address books (OABs).