In Windows NT 4.0-based domains, the space is a legal character in NetBIOS domain names. Windows 2000 domains are DNS based and therefore use DNS names (although a NetBIOS name is available for backward compatibility). DNS doesn�t allow spaces in names. For consistency, Microsoft removed the space as a legal character in Win2K NetBIOS domain names.
Win2K NetBIOS domain names can contain the following special characters:
! @ # $ % ^ & ( ) - _ ' { } . ~The following characters aren�t allowed:
\ * + = | : ; " ? < > ,