Windows 7 / Networking

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Nblookup

Windows Internet Naming Service (WINS) is a NetBIOS name resolution protocol. WINS performs a function for NetBIOS names similar to the function that DNS performs for host names. For many years, WINS name resolution was the most common way for computers running Windows to identify each other on networks. However, in Active Directory Domain Services (AD DS) domain environments, DNS is used by default, and WINS is primarily used to support older clients and applications.

For environments that still rely on WINS servers, Nblookup is a valuable tool for diagnosing WINS name resolution problems. Nblookup is not included with Windows but is available as a free download from http://support.microsoft.com/kb/830578. After saving Nblookup.exe to a computer, you can double-click the file to run it in interactive mode within a command prompt. Alternatively, command-line mode allows you to run it from any command prompt.

The following examples demonstrate the use of command-line mode. To look up a NetBIOS name using the computer's configured WINS server, run the following command.

nblookup computer_name

To look up a NetBIOS name using a specific WINS server, add the /s server_ip parameter, as the following example demonstrates.

nblookup /s server_ip computer_name

For example, to look up the name COMPUTER1 using the WINS server located at 192.168.1.222, you would run the following command.

nblookup /s 192.168.1.222 COMPUTER1

NetBIOS names actually identify services, not computers. If you want to attempt to resolve a NetBIOS name for a specific service, use the /x parameter and specify the service's NetBIOS suffix. For example, the following command would look up domain controllers (which use a NetBIOS suffix of 1C) in a domain named DOMAIN.

nblookup /x 1C DOMAIN

Because WINS is not typically relied on for name resolution by Windows 7 in AD DS environments, troubleshooting WINS name resolution is not discussed further in this tutorial.