Introduction to WINS
Windows Internet Naming Service (WINS) is an older network service (a protocol) that takes computer names as input and returns the numeric IP address of the computer with that name or vice versa. WINS was designed to replace the LMHOSTS file functionality that was used previously on computers and networks utilizing NetBIOS and NetBIOS names. WINS is considered to be a dynamic protocol because it allows hosts, services and users to be registered in the WINS databse on the WINS server automatically when they connect to the network. This saved Network Administrators a great deal of time over having to update and maintain separate LMHOSTS files all over the network.
WINS and DNS
Although WINS performs a similar function to DNS, WINS and DNS are separate protocols and are not related. The format of WINS records is incompatible with DNS as written in the RFC's (DNS domains cannot include an underscore; underscores are permissible in WINS domain names).
WINS has nothing to do with the world-wide network called The Internet. DNS is used by The Internet; WINS is not.
WINS was originally designed for use in a single broadcast domain (and by broadcast we mean broadcasts at the physical/datalink/hardware layer), not in a multiple domain or multi-subnetwork environment. WINS along with NetBIOS names are used to support the "Network Neighborhood" functionality in Microsoft Windows and various Windows proprietary services.
Why WINS Doesn't Work Well in ROuted IP Networks
Routers were created to prevent networks from becoming flooded with broadcasts and to allow networks to grow in size by adding more subnets. By design, router block Internet Protocol (IP) broadcasts (IP transmissions to the destination address 255.255.255.255). Because routers block broadcasts and the standard WINS configuration uses broadcasts exclusively, it is not possible to get WINS working in a multiple subnet environment using the default configuration. Much manual configuration is necessary to enable WINS to work in a routed environment including breaking the router's normal functionality and adding LMHOST files (which WINS was supposed to end the use of in the first place).
WINS was never designed to run on an internet (an internet is two or more networks connected by a router).
WINS is very similar to IBM's NetBIOS Name Server service and was designed to be compatible with it (at least according to Microsoft's documentation). A WINS server is required to provide resolution service to computers on the network.
Computers running the WINS client are referred to by Microsoft as 'nodes'. There are four types of nodes, the difference between them being how they communicate with the other nodes and with the WINS server (if there is one).
| Node Type | Function | WINS Server Required? |
|---|---|---|
| B | Broadcast only node; uses broadcasts only when using WINS. The WINS server will respond to such nodes, if it exists and can 'hear' the broadcast. Hosts functioning as B nodes will provide their own name or IP when asked. B-nodes cannot communicate with each other if there is a router between them. | No |
| P | Point-to-point node; communicates via UDP and TCP to a the WINS server(s). If the servers cannot be communicated with (they are down, the network connection to them is down etc.) the client cannot do resolution and connectivity from the client computer may be severely limited (if it works at all). A NetBIOS name server (a WINS server on Microsoft networks) is required for a P-node to function. | Yes |
| M | Mixed node; tries a broadcast first then tries point-to-point communication with a WINS server. From the standpoint of the volume of network traffic, there is almost no difference between B-nodes and M-nodes. | -- |
| H | Hybrid node; tries a point-to-point communication first ot the WINS server, then tries a broadcast. H-nodes reduce traffic. | -- |
It must be noted that WINS clients cannot 'find' WINS servers dynamically. They must be configured with the WINS servers via DHCP or manually in the Network control panel by your network administrator.
WINS Today
Due to issues using the WINS protocol in routed networks, Microsoft abandoned WINS and moved on to use DNS and Active Directory and recommends disabling WINS on networks which have Active Directory.