How to Configure the Availability Service for Network Load Balanced Computers
Microsoft Exchange Server 2007 will reach end of support on April 11, 2017. To stay supported, you will need to upgrade. For more information, see Resources to help you upgrade your Office 2007 servers and clients.
Applies to: Exchange Server 2007, Exchange Server 2007 SP1, Exchange Server 2007 SP2, Exchange Server 2007 SP3
This topic explains how to use the Exchange Management Shell to configure the Availability service for single forest topologies.
Note
You cannot use the Exchange Management Console to configure the Availability service.
The Availability service improves information workers' free/busy data by providing secure, consistent, and up-to-date free/busy information to computers that are running Microsoft Office Outlook 2007. By default, this service is installed with Microsoft Exchange Server 2007. For single forest topologies, in which all connecting client computers are running Outlook 2007, only the Availability service is used to retrieve free/busy information.
For single forest topologies that contain Exchange 2007 servers and in which the client computers are running Outlook 2007 or Office Outlook 2003 (or earlier), either the Availability service (for the Outlook 2007 clients) or public folders (for the Outlook 2003 (or earlier)) are used to retrieve free/busy information.
For single forest topologies that contain both servers running Exchange 2007 and Exchange Server 2003 and in which the client computers are running Outlook 2007 or Outlook 2003 (or earlier), either the Availability service (for the Outlook 2007 clients) or public folders (for the Outlook 2003 (or earlier)) are used to retrieve free/busy information.
The following table lists the different methods used to retrieve free/busy information in various single forest topologies.
| Client | Logged on mailbox | Target mailbox | Free/Busy retrieval method |
|---|---|---|---|
Outlook 2007 |
Exchange 2007 |
Exchange 2007 |
The Availability service reads free/busy information from the target mailbox. |
Outlook 2007 |
Exchange 2007 |
Exchange 2003 |
The Availability service makes HTTP connections to the /public virtual directory of the Exchange 2003 mailbox. |
Outlook 2003 |
Exchange 2007 |
Exchange 2007 |
Free/busy information is published in local public folders. |
Outlook 2003 |
Exchange 2007 |
Exchange 2003 |
Free/busy information is published in local public folders. |
Outlook Web Access 2007 |
Exchange 2007 |
Exchange 2007 |
Outlook Web Access 2007 calls the Availability service API, which reads the free/busy information from the target mailbox. |
Outlook Web Access 2007 |
Exchange 2007 |
Exchange 2003 |
Outlook Web Access 2007 calls the Availability service API, which makes an HTTP connection to the /public virtual directory of the Exchange 2003 mailbox. |
Any |
Exchange 2003 |
Exchange 2007 |
Free/busy information is published in local public folders. |
Configuring the Availability Server for Network Load Balancing
Outlook 2007 discovers the Availability service URL using the Autodiscover service. The internal URL is used from the intranet, and the external URL is used from the Internet. If you want to use the same URL for both internal and external traffic, make sure that Domain Name System (DNS) is properly configured to route internal traffic directly to the internal Web site. Also, make sure that the URL is properly accessible both internally and externally. For the Autodiscover and Availability services to work, make sure that DNS is properly configured so that mail.example.com and autodiscover.mail.example.com point to the Network Load Balancing (NLB) array of Client Access servers.
Note
For more information about NLB, see Network Load Balancing Technical Reference and Network Load Balancing Clusters. You can also search for third-party load-balancing software Web sites.
For information about diagnosing Availability service issues, see How to Diagnose Availability Service Issues.
For more information about the Autodiscover service, see the Overview of the Autodiscover Service.
Before You Begin
To run the Set-WebServicesVirtualDirectory cmdlet, the account you use must be delegated the following:
- Exchange Server Administrator role and local Administrators group for the target server
For more information about permissions, delegating roles, and the rights that are required to administer Exchange Server 2007, see Permission Considerations.
Procedure
To use the Exchange Management Shell to configure the Availability service for network load balanced computers
Run the following command:
Set-WebServicesVirtualDirectory -Identity "EWS*" -ExternalUrl "Https://Contoso.mail.com/EWS/Exchange.asmx" -InternalUrl "Https://Contoso.mail.com/EWS/Exchange.asmx"
Note
If you have a load balanced set of Client Access servers, you do not have to specify the name of each server when you run the command. You only need to use the name of one of the servers in the network load balanced servers.
For detailed syntax and parameter information, see the Set-WebServicesVirtualDirectory reference topic.
For More Information
For more information about the Availability service, see the following topics:
For more information about the Autodiscover service, see the following topics: