A character string appended to a NetBIOS name of a host that identifies the host as belonging to a specific group. You can use NetBIOS scope IDs to segment the flat NetBIOS namespace into a series of subspaces. Two hosts can communicate only if they have the same NetBIOS scope ID and belong to the same subspace. The total length of a NetBIOS name plus scope ID cannot exceed 256 characters.
The topology of NetBIOS subspaces does not have to match the physical topology of the network or the logical topology of subnets on a TCP/IP internetwork.
Using NetBIOS scope IDs is no longer recommended, especially if you are also using the Domain Name System (DNS) for naming hosts on your network. You should configure NetBIOS scope IDs only if you want to isolate a particular subset of computers on your network from the rest of the network and allow them to communicate only among themselves. (You configure a NetBIOS scope ID on a computer running Microsoft Windows NT 4 by using the WINS Address tab of the TCP/IP property sheet. In Windows 2000, you must manually modify an entry in the registry.)
If trust relationships are configured between several Windows NT domains on your network, using NetBIOS scope IDs can break the effect of these trust relationships by preventing pass-through authentication between trusted domain controllers that have different scope IDs. Furthermore, in a single-domain environment, if the scope ID of a workstation is different from that of the domain controllers, users will not be able to log on to the network at that workstation.