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 2013, this feature is enabled by default, because all Outlook connectivity takes place over Outlook Anywhere.

Outlook Anywhere offers the following benefits to clients that use Outlook 2013, Outlook 2010, or Outlook 2007 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.
  
  
• 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.
  
  

In Exchange 2013, Outlook Anywhere is enabled by default, because all Outlook connectivity takes place via Outlook Anywhere. The only post-deployment task you must perform to successfully use Outlook Anywhere is to install a valid SSL certificate on your Client Access server. Mailbox servers in your organization only require the default self-signed SSL certificate.

You can manage Outlook Anywhere by using the Exchange admin center or the Exchange Management Shell.

If you are planning to install Exchange 2013 in a coexistence scenario with previous versions of Exchange Server, you might still have Outlook 2003 clients in your organization. Outlook 2003 is not a supported client for Exchange 2013.

Before you move your namespace to Exchange 2013, you need to ensure that all Outlook clients have been upgraded to the minimum versions. Outlook 2007 or higher is required for an Outlook Anywhere connection to Exchange 2013, even if the target mailbox is still on Exchange 2007 or Exchange 2010.

You can test for end-to-end client Outlook connectivity by doing either of the following:

• Running the Test-OutlookConnectivity cmdlet. The cmdlet tests for Outlook Anywhere (RPC over HTTP) connections. If the cmdlet test fails, the output notes the step that failed. For detailed syntax and parameters, see Test-OutlookConnectivity.
  
  
• 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. For more information, see Exchange Remote Connectivity Analyzer.
  
  

Both tests try to sign in 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 website, 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 signing in to the user's mailbox