Understanding Outlook Anywhere

Applies to: Exchange Server 2010

Topic Last Modified: 2009-11-04

In Microsoft Exchange Server 2010, the Outlook Anywhere feature, formerly known as RPC over HTTP, lets clients that use Microsoft Office Outlook 2010, Outlook 2007, or Outlook 2003 connect to their Exchange servers from outside the corporate network or over the Internet using the RPC over HTTP Windows networking component. This topic describes the Outlook Anywhere feature, provides information about deploying Outlook Anywhere, discusses coexistence with older versions of Exchange, and lists the benefits of using Outlook Anywhere.

Looking for management tasks related to Outlook Anywhere? See Managing Outlook Anywhere.


Outlook Anywhere and Exchange 2010

Benefits of Using Outlook Anywhere

Deploying Outlook Anywhere

Managing Outlook Anywhere


Outlook Anywhere in Multiple Active Directory Sites


Testing Outlook Anywhere Connectivity

The Windows RPC over HTTP Proxy component, which Outlook Anywhere clients use to connect, wraps remote procedure calls (RPCs) with an HTTP layer. This allows traffic to traverse network firewalls without requiring RPC ports to be opened. In Exchange 2010, as in Exchange 2007, it's easy to deploy and manage this feature. To deploy Outlook Anywhere in your Exchange 2010 messaging environment, you need to enable Outlook Anywhere on at least one Client Access server using the Enable Outlook Anywhere wizard in the Exchange Management Console.

Outlook Anywhere offers the following benefits to clients that use Outlook 2010, Outlook 2007, orOutlook 2003 to access your Exchange messaging infrastructure:

  • Users have remote access to Exchange servers from the Internet.
  • You can use the same URL and namespace that you use for Outlook Web App and Microsoft Exchange ActiveSync.
  • You can use the same Secure Sockets Layer (SSL) server certificate that you use for both Outlook Web App and Exchange ActiveSync.
  • Unauthenticated requests from Outlook can't access Exchange servers.
  • You don't have to use a virtual private network (VPN) to access Exchange servers across the Internet.
  • You don't have to configure anything in Exchange 2010 when you're using SSL session ID load balancing on the Client Access server with Outlook Anywhere.
  • If you already use Outlook Web App with SSL or Exchange ActiveSync with SSL, you don't have to open any additional ports from the Internet.
  • You can test end-to-end client connectivity for Outlook Anywhere and TCP-based connections by using the Test-OutlookConnectivity cmdlet.

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Deploying Outlook Anywhere for your organization is straightforward. The following recommendations should be followed to successfully deploy Outlook Anywhere:

  • Use at least one Client Access server per site   In Exchange 2010, a site is a network location with high-bandwidth connectivity between all computers. We recommend that you install at least one Client Access server in each site to provide client access to the Mailbox server. However, you can have multiple Client Access servers in each site for increased performance and reliability.
  • Enable Outlook Anywhere on at least one Client Access server   We recommend that you have one Client Access server in each site that has Outlook Anywhere enabled. This lets clients that use Outlook 2010 or Outlook 2007 connect to a user's mailbox through the Client Access server in the site. Users will connect by using HTTPS to the Client Access server that's in the site where the user's mailbox is located. This reduces the risk associated with using RPCs across the Internet. Using RPCs across the Internet can adversely affect performance.

For more information, see Enable Outlook Anywhere.

You can manage Outlook Anywhere by using the Exchange Management Console or the Exchange Management Shell. By default, when you enable Outlook Anywhere on a Client Access server, all users who have mailboxes on Exchange 2010 Mailbox servers are enabled for Outlook Anywhere. For more information, see Managing Outlook Anywhere.

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For mailboxes on Exchange 2010 Mailbox servers, clients must connect through Exchange 2010 Client Access servers. Outlook Anywhere can be used in environments where Microsoft Exchange Server 2007 and Exchange Server 2003 servers are still being used. If you have users with mailboxes on Exchange 2003 servers, and these users are using Outlook 2007 or Outlook 2003 to connect, you must configure these clients manually. To configure Outlook Anywhere with Exchange 2007 or Exchange 2003, see Configure Outlook Anywhere in an Environment with Earlier Versions of Exchange.

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If you have multiple Active Directory sites that are separated by low-bandwidth network connectivity, you can enable a Client Access server in each site. The Autodiscover service will then automatically detect which Client Access server is closest to the user's mailbox that resides either on an Exchange 2003 back-end server enabled for RPC over HTTP or on a later Exchange version running the Mailbox server role. After the user has connected across the Internet using RPC over HTTP, the Client Access server will then use RPC requests. This ensures that RPC requests stay within the site's intranet. For more information about how to provide an external host name for Outlook Anywhere, see Configure an External Host Name for Outlook Anywhere.

Users with mailboxes on Exchange Server 2003 servers with SP1 or a later version or Exchange 2003 servers enabled for RPC over HTTP will also be able to access their Exchange information from the Internet. For these users, you can use the Shell to manage the Outlook Anywhere feature on the Exchange 2010 Client Access server in the site.

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After you enable Outlook Anywhere in your Microsoft Exchange Server 2010 organization, you can test for end-to-end client Outlook connectivity. You can test end-to-end Outlook connectivity by doing either of the following:

  • Running the Test-OutlookConnectivity cmdlet. The cmdlet tests for Outlook Anywhere (RPC over HTTP) and TCP/IP connections. If the cmdlet test fails, the output notes the step that failed.
  • Running the Outlook Anywhere connectivity test using the Exchange Remote Connectivity Analyzer (ExRCA). When you run this test, you get a detailed summary showing where the test failed and what steps you can take to fix issues.

Both tests try to log on through Outlook Anywhere after obtaining server settings from the Autodiscover service. End-to-end verification includes the following:

  • Testing for Autodiscover connectivity
  • Validating DNS
  • Validating certificates (whether the certificate name matches the Web site, whether the certificate has expired, and whether it's trusted)
  • Checking that the firewall is set up correctly (ExRCA checks overall firewall setup. The cmdlet tests for Windows firewall configuration.)
  • Confirming client connectivity by logging on to the user's mailbox

For more information, see Test Outlook Anywhere Connectivity.

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