TCP/IP and Windows Internet Name Service

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The Windows Internet Name Service (WINS) is a service that maps network basic input/output system (NetBIOS) names to IP addresses. In versions of Windows earlier than Windows 2000, WINS is used in conjunction with DHCP to register NetBIOS names and dynamically-assigned IP addresses with the WINS database In this case, a DHCP-enabled host queries a DHCP server for an IP address, the DHCP server then allocates a WINS server to the DHCP client as a DHCP option. After the DHCP lease allocation process is complete, the NetBIOS name and its associated IP address are registered in the WINS database by the DHCP client.

Windows 2000 provides integration between DNS and WINS. If a Windows 2000 DNS server cannot resolve a fully qualified domain name (FQDN), it converts the FQDN to a NetBIOS name and queries a configured WINS server. The IP address returned by the WINS server is forwarded to the DNS client.

In Windows 2000, you do not need WINS and NetBIOS over TCP/IP if you are using only Windows 2000 servers and clients. If you use systems such as Windows NT version 3.5 x , Windows NT 4.0, Windows 95, Windows 98, or Windows 3. x , WINS is still required because those operating systems use NetBIOS name resolution and NetBIOS sessions to create file and print sharing connections.

WINS Design Considerations

If NetBIOS name resolution is required, you need to determine the number of WINS servers that you need. Consider the location of routers on your network and the distribution of clients in each subnet. On a smaller network, a single WINS server can service up to 10,000 clients for NetBIOS name resolution requests. Larger networks require more, depending the number of client connections there are per server. You can install the WINS server on the same system as the DNS server, or you can install it separately. You also need to install a backup WINS server elsewhere in the network. You can install the backup WINS server on the same system as a Windows 2000 domain controller, or you can install it separately.

note-icon Update

The first printing of this book states that "If NetBIOS name resolution is required, each site within a domain needs to have at least one WINS server." The previous paragraph in this online version contains more up-to-date information.