Name Resolution

With WINS servers in place on the internetwork, NetBIOS computer names are resolved using two basic methods depending on whether WINS resolution is available and enabled on the client computer. Regardless of which name resolution method is used, the process is not visible to the user after the system is configured.

• If WINS is not enabled on the client - The computer registers its name by sending name registration request packets (as broadcast messages) to the local subnet. To find a particular computer, the non-WINS computer sends name query request packets (as broadcast messages) on the local subnet. (This broadcast message cannot be passed on through IP routers.) If local name resolution fails, the local LMHOSTS file is consulted. These processes are followed whether the computer is a network server, a workstation, or another device.

• If WINS is enabled on the client - The computer first queries the WINS server. If this fails, it sends name registration and query requests (as broadcast messages) in the following series of steps:

  1. A client's name query request is sent first to the WINS server. If the name is found in the WINS database, then the client can establish a session based on the address mapping received from the WINS server.

  2. If the WINS server query is unsuccessful and if the client computer is configured as an h-node, the client computer sends name query request packets (as broadcast messages) in the same manner as a non-WINS-enabled computer.

  3. Finally, if other methods fail, the local LMHOSTS file is checked. (Included in the search are any centralized LMHOSTS files referred to in #INCLUDE statements in the local file.)

WINS servers accept and respond to User Datagram Protocol (UDP) name queries. Any name-to-IP address mapping registered with a WINS server can be provided reliably as a response to a name query. However, a mapping in the database does not ensure that the related device is currently running, only that a computer claimed the particular IP address and that it currently is a valid mapping.