All non-MAPI messaging clients that access a mailbox in Exchange 2007 connect to an Exchange Server computer that has the Client Access server role installed. The Client Access server role can be installed on a computer that is running any of the other Exchange server roles except the Edge Transport server role. When clients access mailboxes on an Exchange server that has the Mailbox server role installed by using Office Outlook Web Access, Outlook Anywhere, Exchange ActiveSync, POP3, or IMAP4 clients, they connect to a Client Access server that communicates directly with the Mailbox server.

Note:
The Client Access server role and the Mailbox server role can be installed on the same Exchange Server 2007 computer. In this case, the Client Access server role handles the client request and communicates with the Mailbox server role processes all on the same computer.

Exchange 2007 provides several new features in Exchange ActiveSync. Some of these features are as follows:

• Support for HTML messages
  
• Support for follow-up flags
  
• Support for fast message retrieval
  
• Meeting attendee information
  
• Enhanced Exchange search
  
• Windows SharePoint Services and Windows file share document access
  
• Global address list search
  
• Password reset
  
• Expanded device password security policy settings
  
• Support for Out of Office configuration
  
• Self-service device management support through Outlook Web Access
  
• Integrated device management support in the Exchange Management Console
  
• Support for allowing device synchronization by device ID
  
• Support for tasks synchronization
  
• Direct Push
  

Note:
Many of these features are available only with the latest release of the Windows Mobile client software.

Note:
When you use Exchange ActiveSync and a mobile device to access Unified Messaging, you can download and listen to the attached .wma file for voice mail messages.

For more information about Exchange ActiveSync, see the following topics: 

• Overview of Exchange ActiveSync
  
• Managing Exchange ActiveSync
  
• Client Features in Exchange ActiveSync
  

Outlook Web Access has several new and enhanced features in Exchange Server 2007. Some of those features include the following:

• New integrated search and advanced search capabilities.
  
• Improved message view. This includes grouping and sorting features, message flags, and conversation view.
  
• Improved browsing and searching of Contacts and Address Book information.
  
• Enhanced calendar viewing. This includes meeting booking improvements and color categories.
  
• Integrated reminders.
  
• Always up to date mail delivery.
  
• Advanced Out of Office scheduling and enhanced Out of Office management.
  
• Mobile device management.
  
• Improved experience for limited vision users.
  

  Caution:
  When you use Pocket Internet Explorer to access Outlook Web Access Light, you may be able to listen to a voice mail message that is attached to an e-mail message. However, this functionality is not supported because Pocket Internet Explorer is not a supported platform for Outlook Web Access Light.

For more information about Outlook Web Access, see the following topics:

• Overview of Outlook Web Access
  
• Client Features in Outlook Web Access
  

The Outlook Anywhere feature for Exchange 2007, formerly known as RPC over HTTP, provides access to your Exchange messaging environment for Microsoft Outlook 2003 or Outlook 2007 clients that connect to Exchange over the Internet. If you have installed the RPC over HTTP Proxy Windows networking component in Windows Server 2003 and enabled Outlook Anywhere on a computer that has the Client Access server role installed, users can use Outlook 2003 or Outlook 2007 to connect to their Exchange 2003 or Exchange 2007 mailbox by using Outlook Anywhere. By enabling Outlook Anywhere, Internet-based users have a reliable and efficient way to connect to their Exchange mailbox without having to create a virtual private network (VPN) connection to the corporate network.

For more information about Outlook Anywhere, see the following topics: 

• Overview of Outlook Anywhere
  
• Managing Outlook Anywhere
  

Exchange 2007 enables you to use the Post Office Protocol version 3 (POP3) and Internet Message Access Protocol version 4 rev 1 (IMAP4) to support clients that still rely on these protocols. By default, both the POP3 service and the IMAP4 service are disabled for new installations of Exchange. Additionally, both protocols have limited access to calendar information for Exchange Server. The basic functionality of these two protocols is as follows:

• POP3   POP3 was designed to support offline mail processing. With POP3, e-mail messages are removed from the server, unless specified differently on the client, and stored on the local POP3 client. This puts the data management and security responsibility in the hands of the user.
  
• IMAP4   IMAP4 offers offline and online access, but like POP3, IMAP4 does not offer advanced collaboration features such as scheduling and group scheduling and task and contact management.
  

For more information about POP3 and IMAP4, see Managing POP3 and IMAP4.

Exchange 2007 includes a suite of new components that are designed to give users an enhanced calendar experience. The following components are included:

• Calendar Attendant
  
• Scheduling Attendant
  
• Resource Booking Attendant
  
• Availability Service
  

For more information about these calendar features, see Client Features in Outlook Web Access.

Calendar Attendant

Scheduling Assistant

Resource Booking Attendant

Availability Service

Exchange 2007 includes several new and enhanced Out of Office features. These features include the following functionality:

• Users can schedule a future Out of Office time so that they do not have to remember to set their status to Out of Office.
  
• Users can create two different Out of Office messages, one for external users and one for users within their own organization.
  
• Users can decide to send their external Out of Office message only to external recipients who are in their Contacts list.
  
• The Out of Office message is sent in HTML instead of plain text.
  

Administrators can manage the external Out of Office feature at the mailbox level. They can configure external Out of Office on a per-user and per-domain basis.

The Autodiscover service is a new feature in Exchange 2007 that automatically provides configuration information to Outlook and supported Exchange ActiveSync devices. In earlier versions of Microsoft Exchange, users were required to configure several settings to configure their profile. These settings included server name, mailbox name, and user account information. With the Autodiscover service in Exchange 2007, users need to provide only their e-mail address and password. The Autodiscover service returns an XML file that contains the user's configuration information. The Outlook 2007 client or supported Exchange ActiveSync device uses this information to create the user's profile. In addition to facilitating profile creation, the Autodiscover service also repairs any Exchange connection settings after a change has been made to the server settings or the user's profile.

Table 1 lists the client applications and protocols that support the use of the Autodiscover service.

Table 1   Client applications and protocols that support the Autodiscover service

For more information about the Autodiscover service, see the following topics:

• Managing the Autodiscover Service
  
• How to Create a New Autodiscover Service Virtual Directory