19.2 Sociology

The Browse Service, as was stated earlier, has a social structure. SMB servers and clients are expected to be members of cliques known as "workgroups" or "domains." The basic difference between a workgroup and a domain is that the latter provides central authentication services via Domain Controllers.

Just to make life more interesting, there are two types of domain to consider:

Windows 2000 Domains

As explained above, Windows 2000 provides a browse system that is based on Directory Services (Active Directory, etc.). W2K Domains are not NBT-based, so they do not use NetBIOS names . Instead, W2K Domains are closely aligned with the Domain Name System (DNS) and rely on Kerberos for authentication. This is Microsoft's way of grafting their domain architecture onto the Internet Domain Name System.

Windows NT Domains

NT Domains are glorified workgroups, but that's not a particularly helpful description since we haven't really explained what a workgroup is yet.

A workgroup, quite simply, is defined by its NetBIOS name. The workgroup name is typically assigned in the node's configuration, although utilities like smbclient and toolkits like jCIFS allow the workgroup name to be specified at run-time. As with the node's machine name, the workgroup name is used as the basis for NetBIOS names that are actually registered just add the appropriate suffix byte. Systems do not need to register any name based on the workgroup unless they are offering services to the workgroup as a whole. Some example workgroup names:

Name & Suffix	Group /Unique	Service/Description
workgroup <00>	group	This name is a remnant of the original LAN Manager browse service.
workgroup <1D>	unique	This name identifies the Local Master Browser (LMB, sometimes called simply "Master Browser") for a subnet.
workgroup <1E>	group	Every node that is capable of acting as a "Browser" registers this group name so that it can listen for election announcements. We'll explain what a "Browser" is in a moment.

That just scratches the surface, and doesn't really tell us anything about NT Domains. Fully explaining what workgroups and NT Domains are all about and how the names listed above are used is something of a recursive problem because the sociology of the Browse Service is intertwined with the politics.