Microsoft has written a Knowledge Base article on this subject, at Q258750, that applies to Windows 2000 and Windows NT 4.0. It begins with:
"To eliminate possible communication issues, remove all unnecessary network traffic from the network adapter that is set to Internal Cluster communications only (this adapter is also known as the heartbeat or private network adapter). Clustering communicates by using Remote Procedure Call (RPC) calls on IP sockets with User Datagram Protocol (UDP) packets. The process described in this article:
Removes NetBIOS from the interconnect.
Sets the proper Cluster communication priority order.
Sets the proper adapter binding order.
Defines the proper network adapter speed and mode.
Configures TCP/IP correctly.
Disable the Media Sense feature (in Windows 2000 only)."