Registering names

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Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2, Windows Server 2008, Windows Server 2008 R2, Windows Server 8 Beta

Registering names

Name registration is a WINS client requesting the use of a NetBIOS name on the network. The request may be for a unique (exclusive) or a group (shared) name. NetBIOS applications can also register one or more names.

As illustrated in the following figure, a WINS client (HOST-C) sends a Name Registration Request directly to its configured WINS server, WINS-A.

How clients register in WINS

WINS-A can accept or reject the name registration request by issuing either a positive or negative name registration response to HOST-C. The action taken by WINS-A depends on several factors:

  • Whether the name already exists in the server database at WINS-A

  • If a record of the name exists, the state in the server database of the record at WINS-A might make a difference. Also, if the recorded IP address for the name is the same or different from the IP address of the requesting client, HOST-C.

  • Whether the request is for a unique or group name entry.

If the name does not exist in the database, it is accepted as a new registration and the following steps occur:

  1. The name for HOST-C is entered with a new version ID, given a time stamp, and marked with the owner ID of the WINS server.

    The time stamp is calculated based on adding the value of the Renew interval (which by default, is 6 days) set on the WINS server to the current date and time of the server.

  2. A positive registration response is sent back to HOST-C with a Time-to-Live (TTL) value equal to the time stamp recorded for the name at WINS-A.

Name registered for same IP address

If the name HOST-C is already entered in the database with the same IP address as that being requested, the action taken depends on the state and ownership of the existing name.

  1. If the entry is marked as active and the entry is owned by the server (WINS-A), the server updates the time stamp for the record and returns a positive Response back to the client.

  2. If the entry is marked as being either released or tombstoned, or if the entry is owned by another WINS server, the registration is treated as a new registration. Time stamp, version ID, and ownership are all updated and a positive response is returned.

Name registered for different IP address

In the case where the name exists in the WINS database but with a different IP address than that being requested, the WINS server is expected to avoid duplicate names. If the database entry is in the released or tombstone state, the WINS server is free to assign that name.

If, however, the entry is in the active state, the node holding the name is challenged to determine if it still exists on the network. In this case, the WINS server (WINS-A) could perform a challenge of the name and do the following:

  1. WINS-A sends a Wait for Acknowledgment (WACK) response to the requesting client (HOST-C), specifying a time in the TTL field that the client should be prepared to wait for a response.

  2. WINS-A then issues a name query request to the node currently registered for this name in the server database.

  3. If the node still exists, it sends a positive response back to WINS-A.

  4. WINS-A, in turn, sends a negative name registration response back to the requesting client (HOST-C), rejecting the name registration.

  5. If a positive response is not received back from the first challenge query made by WINS-A, two subsequent name query requests are made. After three attempts with no response, the challenge process is complete and a positive registration response is returned to the requesting client (HOST-C) and the name updated in the server database for the new client registration.

Notes

  • Unlike WINS-enabled clients, which can directly contact a WINS server, non-WINS clients (such as NetBT b-node clients) must register and then continuously defend their names by sending and replying to broadcast name queries within the local network.

  • NetBIOS names are registered with the Windows Internet Name Service (WINS) and are normally released when the computer is properly shutdown. If the computer was not properly shutdown, or the computer was not able to contact a WINS server during shutdown, the nbtstat command can be used to refresh in WINS the local names for this computer. This can be useful for mobile or portable computers that are moved between different locations on a network.

    For more information, see Verify WINS registration of client NetBIOS names.