Exchange 2010 installs a whole range of new services during installation. Here I explain which service is needed for which purpose.
21 New services are installed on an Exchange Multi Role Server
Microsoft Exchange Active Directory topology
This service is used to retrieve the topology information of the Active Directory. This service is used to determine the Active Directory location and other Exchange servers at the location
Microsoft Exchange EdgeSync
The EdgeSync service supplies the Exchange EdgeTransport servers with data. In order for the EdgeTransport servers to know which recipients there are in the internal Exchange organization, this data must be communicated to the EdgeTransport servers, as they do not have a direct connection to the Active Directory.
Microsoft Exchange IMAP4
Alternative clients that do not support MAPI can access Exchange via IMAP. The IMAP4 service provides this functionality.
Microsoft Exchange POP3
Alternative clients that support neither MAPI nor IMAP can also access Exchange via the POP3 protocol. In practice, however, this is rarely used. The POP3 service makes the POP3 protocol available to these clients.
Microsoft Exchange Server Extension for Windows Server Backup
This service provides an interface for Windows Server backup, with which the Exchange database can be backed up online. The backup is based on VSS. The corresponding VSS writers are also set up by this service. As far as I know, this service is only used by Windows Server Backup. Most backup programs come with their own agents to be able to back up Exchange.
Microsoft Exchange address book
This service manages the Exchange address books. Clients can connect to the service to download the offline address book. This service also takes care of updating the address book.
Microsoft Exchange antispam update
This service is used to download updates for Microsoft Forefront Protection for Exchange 2010. Information about Forefront Protection for Exchange can be found here
Microsoft Exchange file distribution
The offline address book is replicated to the CAS servers using the file distribution service. An Exchange server creates the address book and replicates it to the other CAS servers using file distribution.
Microsoft Exchange service host
The service host enables access to Exchange via Outlook Anywhere (RPCoverHTTPS). The service host controls the virtual directory "RPC" in the IIS
Microsoft Exchange restrictions
All limits and restrictions for mailboxes or messages are controlled with the "Restrictions" service. This includes, for example, upper mailbox limits or the maximum message size
Microsoft Exchange Information Store
The Information Store service manages the Exchange databases. The databases cannot be accessed without this service. This includes mailbox and public folder databases.
Microsoft Exchange mail transfer
This service is responsible for the delivery of mails from mailbox to mailbox, from mailbox to EdgeTransport and from mailbox to internal recipient.
Microsoft Exchange Mailbox Wizard
The Mailbox Assistant service is responsible for out-of-office messages, automatic replies and automatic calendar booking. Mailbox rules are also controlled via this service.
Microsoft Exchange mailbox replication
Remote and local move requests require the mailbox replication service. This service enables mailboxes to be moved within the Exchange organization or across organizations.
Microsoft Exchange Replication
DAGs require the Replication service to replicate the databases and transaction logs to other mailbox servers.
Microsoft RPC client access service
This service is responsible for all RPC communication between the client and the CAS server. Outlook cannot access Exchange without this service.
Microsoft Exchange search indexing
As the name suggests, search indexing builds the search index for all mailboxes. This ensures a quick index search via Outlook and OWA. The index is saved together with the database in a subdirectory "CatalogData".
Microsoft Exchange System Supervision
Exchange System Supervision controls the Exchange services and monitors them. In addition, the system supervisor establishes the interface between Exchange and the Active Directory in order to read or write information from the AD.
Microsoft Exchange Transport
The Transport service provides the SMTP server. Mails cannot be sent to Exchange without this service.
Microsoft Exchange transport protocol search
This service searches the message tracking logs and prepares the information for the user.
Microsoft Exchange monitoring
This service is used to start the CMDLets diagnostics and write them to the event log.
