The Directory Service Proxy (DSProxy) component in Microsoft Exchange Server 2003 Service Pack 2 (SP2) has been updated with a new algorithm. This article contains information about the updated DSProxy component.

DSProxy is the component in Microsoft Exchange Server 2003 that provides an address book service to Microsoft Outlook clients. Although the name implies that this component provides only proxy services, DSProxy provides both of the following services:

1.	DSProxy emulates a MAPI address book service and sends proxy requests to an Active Directory server.
2.	DSProxy refers Outlook client queries to an Active Directory server.

The updated DSProxy component in Exchange Server 2003 SP2 is more selective than the older DSProxy component when the component refers Outlook clients to global catalog servers. This improved selectivity makes directory requests from the client more efficient. For more information about the DSProxy component, visit the following Microsoft TechNet Web site: