Windows Internet Name Service (WINS) is Microsoft's implementation of NetBIOS Name Service (NBNS), a name server and service for NetBIOS computer names. Effectively WINS is to NetBIOS names what DNS is to domain names — a central mapping of host names to network addresses. Like DNS it is broken into two parts, a Server Service (that manages the encoded Jet Database, server to server replication, service requests, and conflicts) and a TCP/IP Client component which manages the client's registration and renewal of names, and takes care of queries.
Network address mappings are dynamically updated so that when a client needs to contact another computer on the network it can get its up-to-date IP address which may be issued by a DHCP server. Aside from this the WINS functionality provides a way of keeping the client names unique on the network.
Networks normally have more than one WINS server and each WINS server should be in push/pull replication; where more than two WINS servers are required the best practice replication model is the hub and spoke, thus the WINS design is not central but distributed. Each WINS server holds a full copy of every other related WINS system's records. There is no hierarchy in WINS (unlike DNS), but like DNS its database can be queried for the address to contact rather than broadcasting a request for which address to contact. The system therefore reduces broadcast traffic on the network, however replication traffic can add to WAN/LAN traffic, although this can be set to replicate in non busy periods. By design any WINS client can register any name with any WINS server. This makes the system prone to abuse or unreliable through poor administration.
All WINS clients should be configured to use a primary WINS server and a different secondary WINS server. The secondary would normally be the hub server. The setting of which WINS servers to use is either in the DHCP scope options or a per client hard coded value.
As of Windows 2000, DNS provides the favored alternative to WINS, as part of Active Directory.[1]
In theory, if DNS is available, WINS is only necessary if pre-Windows 2000 clients or servers need to resolve names. In reality, especially in large enterprise environments, applications such as SMS 2003 with its use of the 1A record, MS SQL Server 2000 for use of named pipes, and Exchange Server 2000 and 2003 both require WINS for full functionality.[2]
The WINS server from Microsoft is only available as a service to run on the Windows Server family of operating systems. Other system are able to run WINS server from Samba package. The WINS client from Microsoft is common across all its operating systems including DOS. WINS clients can also be devices such as IP phones and printers through Samba or by other implementation.