Here's a special note for switched-network environments. If you plug your Windows NT Load Balancing Service (WLBS)based Web servers into switches and your virtual IP address is on a different network segment than your dedicated IP addresses, you might run into a known problem between the network switches and WLBS. For WLBS to work, each node in the cluster has to receive the same incoming Web request. However, network switches often learn a media access control (MAC) address on a port-by-port basis and associate the address with the port. This behavior kills WLBS's functionality. For more information about this behavior, see the Microsoft article "Configuration Options for WLBS Hosts Connected to a Layer 2 Switch" (http://support.microsoft.com/default.aspx?scid=kb;en-us;q193602), or see the article "MS Windows Load Balancing Server: Issues with Switching and Routing" (http://www.cisco.com/warp/public/473/ms_wlbs.html).