Windows Internet Name Service, or WINS, is a Microsoft Windows NT, Windows 2000 or Windows 2003 service that dynamically registers NetBIOS names of computers on the network. It also provides a central location for resolving these NetBIOS names into IP addresses. Windows Internet Name Service (WINS) is a popular name resolution service on Windows NT networks because it is dynamic, rather than static, making it easier to manage than the Domain Name System (DNS). On the Windows 2000 platform, however, DNS is the main name resolution method now used, while WINS is optionally available as a location service for supporting downlevel (Windows NT, Windows 98, Windows 95, and Windows for Workgroups) servers and clients on the network.
In order for NetBIOS hosts (servers and clients running pre–Windows 2000 versions of Microsoft Windows) to communicate on a network, their NetBIOS names must first be resolved into IP addresses. WINS servers, which are servers running Windows NT or Windows 2000 with WINS installed, perform this task. Using WINS servers instead of broadcasts to perform NetBIOS name resolution has several advantages:
WINS works by requiring each NetBIOS host to register its NetBIOS name to IP address mapping on the WINS server by using a process called name registration. These mappings are temporarily stored in a database called the WINS database and need to be renewed periodically by way of a process called registration renewal. If the IP address of the NetBIOS host changes, the WINS database is automatically updated accordingly. And when a NetBIOS host is shut down, a name release occurs, removing the host’s associated mapping from the WINS database.
If a client computer (typically a computer running Windows NT Workstation, Windows 98, Windows 95, or Windows for Workgroups) wants to connect to a file server running Windows 2000 or Windows NT, it queries a designated WINS server using a name query, providing it with the NetBIOS name of the file server it wants to connect to. The WINS server checks its database and responds to the client with the IP address of the desired file server, enabling the client to locate and connect to the file server.
On the Windows NT Server platform, you manage WINS by using the administrative tool called WINS Manager. This tool can be used for the following tasks:
On the Windows 2000 Server platform, you manage WINS using the WINS snap-in for the Microsoft Management Console (MMC).
A single WINS server can support up to about 5000 clients. However, it is a good idea to always use at least two WINS servers in order to provide fault tolerance for NetBIOS name resolution. WINS servers maintain their own separate WINS databases, but they can be configured to replicate their NetBIOS name to IP address mappings by way of a process called WINS database replication.