Mapping Multiple Proxy Addresses to Multiple Back-End Virtual Root Directories on the Same Server Is Not Supported

In Exchange Server 2003, there is no option to map multiple proxy addresses (for multiple front-end Microsoft Outlook Mobile Access virtual servers) to multiple back-end virtual root directories on the same server.

Exchange Server 2003 does not support the mapping of multiple proxy addresses to multiple back-end virtual root directories on the same computer. By default, /Exchange is used as the back-end virtual root directory.

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk. To work around this behavior, set the ExchangeVDir value in the following registry key to the virtual directory that you want to use: To set the ExchangeVDir value to specify a virtual directory, follow these steps:

1. Click Start, and then click Run.
2. In the Open box, type regedit, and then click OK.
3. Locate, and then double-click the following registry key:
   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MasSync\Parameters
4. In the right pane, double-click ExchangeVDir.
   
   Note If the ExchangeVDir value does not exist, create it. To do so:
   1. On the Edit menu, point to New, and then click String Value.
   2. Type ExchangeVDir, and then press ENTER.
5. In the Value data box, type /VirtualDirectory (where VirtualDirectory is the name of the virtual directory that you want to use), and then click OK.
6. Quit Registry Editor.

The HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MasSync\Parameters\ExchangeVDir registry entry is used by Outlook Mobile Access and by Microsoft Exchange Server ActiveSync. It specifies the virtual directory that Outlook Mobile Access and Exchange Server ActiveSync use to access Microsoft Outlook Web Access templates and World Wide Web Distributed Authoring and Versioning (WebDAV) on the Exchange Server 2003 back-end servers where user mailboxes are located.

If the ExchangeVDir entry does not exist, or if a value is not set for it, the default value of /Exchange is used. Otherwise, it contains the name of the virtual directory (including the forward slash character "/"). You can configure this value when you want to specify a virtual directory for Outlook Mobile Access or Exchange Server ActiveSync.