Windows 2000 WINS

The purpose of WINS is to allow a NetBIOS name to be converted to an IP address. Therefore computers using WINS must be using NBT (NetBIOS over TCP/IP). WINS was originally put in place to compensate for a shortcoming of NetBEUI which is the fact that it is not routable. Therefore on large Networks IP is used to transport NetBIOS and rather than using broadcasts, information is sent to the WINS server.

WINS converts Windows computer names to IP addresses but does not do name lookups based on IP addresses. The use of Windows Explorer or NET commands invokes the NetBIOS interface. NetBIOS names, if repeated on another domain that is on the network, may cause a problem since there is no way to distinguish NetBIOS names between two domains. Each computer, when booted, sends a name registration broadcast. If there is no response, the computer will use the name it registered. A NetBIOS broadcast releases the computer name when the computer is shutdown gracefully.

WINS reduces this broadcast traffic when using NBT. The registration and release is sent to the WINS server rather than being broadcast. The clients have the IP address of the WINS server and they are configured to use WINS before using NetBIOS broadcasts. A backup WINS server may be available on the network for fault tolerance.

Five NBT Name Resolution Methods

• B-node - broadcast - Uses UDP broadcast datagrams. Default node type.
• P-node - Peer to peer - Uses a NetBIOS name server such as WINS. If a WINS server is not available, broadcasts are not used as a backup. The WINS IP address must be specified at each client?
• M-node - Mixed - Tries B-node, then P-node resolution.
• H-node - Hybrid - Tries P-node, then B-node resolution. After this attempt for Windows 2000, LMHOSTS and HOSTS files are used, then the DNS server is used.
• Microsoft enhanced B-node - Checks address cache which is loaded brom the lmhosts file when the system boots. After checking address cache, a broadcast is sent, then the lmhost file is checked if broadcasting did not resolve the query.