Determining if You Need to Support NetBIOS Names

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

During a domain upgrade to Windows Server 2003, you might need to support NetBIOS on your network if your domain includes clients that are running versions of Windows earlier than Windows 2000. For example, if your network is multi-segmented, WINS is required to create the NetBIOS browse list. Without WINS, the network must rely on Active Directory for browsing resources. This can have a significant impact on clients that are running applications that require NetBIOS support, even if the client operating system does not require NetBIOS support. When WINS is installed, performance monitor counters for WINS are also installed. Use these WINS performance monitor counters to determine how many queries WINS is receiving, and how many names WINS is resolving. This information will help you to determine whether it is necessary to support NetBIOS names on the network.

Windows Server 2003 DNS is compatible with WINS; therefore, in a mixed networking environment, you can use a combination of DNS and WINS. Windows NT 4.0–based clients can register in both Windows 2000 WINS and Windows Server 2003 WINS. Also, computers running either the Microsoft® Windows® 2000 Professional or Windows® XP Professional operating systems can register in Windows NT 4.0 WINS. To maintain backward compatibility, each computer is given a NetBIOS name that must be unique in the domain to which the computer belongs.

Preserving existing NetBIOS names can be difficult because NetBIOS names have a broader character set than DNS names. One solution is to replace NetBIOS names with DNS names to ensure that the names adhere to existing DNS naming standards. This is not possible for organizations that support computers running versions of Windows earlier than Windows 2000.

RFC 2181: Clarifications to the DNS Specification expands the character set that is allowed in DNS names to include any binary string. The binary strings do not have to be interpreted as ASCII. Windows 2000 and Windows Server 2003 support UTF-8 character encoding (RFC 2044). UTF-8 is a superset of ASCII and a translation of the UCS-2 (or Unicode) character encoding. The UTF-8 character set enables you to transition from Windows NT 4.0 NetBIOS names to Windows 2000 and Windows Server 2003 DNS names

By default, multibyte UTF-8 name checking is used. This provides the greatest tolerance when the DNS service processes characters. This is the preferred name-checking method for most DNS servers that are not providing name resolution services for Internet hosts.


  • Windows Server 2003 and Windows 2000 DNS support NetBIOS and UTF-8 characters for computer names. Other versions of DNS only support the characters permitted in RFC 1123. Therefore, only use NetBIOS and UTF-8 character sets when you are certain that Windows Server 2003 or Windows 2000 DNS is the method used for name resolution. Names that are intended to be visible on the Internet must contain ASCII-only characters, as recommended in RFC 1123.