If your Outlook client successfully connects to Exchange Server, but the initial client startup is exceptionally slow (longer than 60 seconds), you can perform a couple of checks to determine the problem. First, you can use the Network Monitor tool to identify significant latencies (i.e., longer than 500 milliseconds-ms) in the packets in transit between the client PC and the Exchange server. The Network Monitor tool is available in Windows Server 2003 and Windows 2000 Server. However, you must add this tool. In the Control Panel, double-click Add or Remove Programs and click Add/Remove Windows Component. From the drop-down list, select Management and Monitoring Tools, then click Next, Finish.
Second, you can check the Rpc_Binding_Order entry in the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Exchange\Exchange Provider registry subkey. The Rpc_Binding_Order entry defines the order in which the various network protocols are tried when you're attempting to establish a connection between the Outlook client and the Exchange server. If unsupported protocols are tried first, they must timeout before the next protocol can be tried. Figure A shows the default settings for the Rpc_Binding_Order registry key on Windows XP Service Pack 1 (SP1) with Outlook 2003. As Web Figure A shows, a local remote procedure call (RPC) is tried first, followed by an IP connection, then an SPX connection, and so on. Note that the nca prefix is an acronym for Network Connection Architecture. This binding order tends not to be too much of a problem nowadays because most clients use TCP/IP, but this problem might surface from time to time.