NetBIOS Domain Names

Windows 2000 provides support for applications that use the NetBIOS networking API and the flat NetBIOS names used by these applications. This support for non-DNS domain and computer names allows computers that are running Windows NT 4.0 and earlier, or those that are running Windows 95 or Windows 98, to identify Windows 2000 domains. For example, in a mixed-mode environment, Windows NT 4.0–based backup domain controllers (also known as "BDCs") recognize a specified Windows 2000–based domain controller as the primary domain controller (also known as a "PDC"). They use NetBIOS names to locate the primary domain controller; therefore, each Windows 2000–based domain controller must have a NetBIOS name to allow computers that are not running Windows 2000 to log on. Likewise, other server and workstation computers are recognized by NetBIOS names.

When you create a new domain during the Active Directory installation procedure, the system provides a default NetBIOS domain name that matches the leftmost label in the DNS domain name up to the first 15 bytes (NetBIOS names have a limit of 15 bytes). You can change this name during the procedure, but you cannot change it thereafter. When you name a stand-alone server or workstation computer, you provide a computer name that is used as the NetBIOS name and is concatenated with the domain name to form the full computer name.


An ASCII character is the equivalent of 1 byte. However, DNS host names are encoded in UTF-8 format and do not necessarily have only 1 byte per character.

For more information about DNS domain names, computer names, and host names, see "Windows 2000 DNS" in the TCP/IP Core Networking Guide . For more information about the Active Directory installation procedure, see "Name Resolution in Active Directory" in this book.