Microsoft Outlook 2000 is Slow When Connecting to Exchange Server
Clients using Outlook who are connected to a corporate Exchange server over DSL (with or without VPN) will often experience slow performance in handling messages. The problem is most severe with large messages, and opening attachments of any size can slow Outlook to a crawl. Thankfully, there is an easy solution.
Outlook, by default, attempts to connect to Exchange servers with RPC (Remote Procedure Call,) TCP/IP, IPX/SPX, and even banyan vines. Meanwhile, the user is waiting for their message to display. Limiting Outlook to TCP/IP only will frequently make a world of difference in Outlook's responsiveness. To do that, you must edit the registry. See warning (opens in a new window) before modifying the registry.
Open regedit and navigate to the following key:
HKLM\SOFTWARE\Microsoft\Exchange\ExchangeProviders
Modify the key, deleting removing everything but TCP/IP, leaving just ncacn_ip_tcp.
If you prefer, you can copy and paste the following text into notepad, save it as a .reg file, and merge it with the registry. This file only works for Windows 2000 and XP . For Windows 98, just manually make the above registry edit on one system, then export the key to get a .reg file that will work with Windows 98 systems.
Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Exchange\Exchange Provider] "Rpc_Binding_Order"="ncacn_ip_tcp"
Our users connecting to Exchange over VPN connections have reported that this change makes a very big difference in the responsiveness of Outlook.