Windows NT uses the Computer Browser service
to collect and display all computers and other resources on the
network. For example, opening Network Neighborhood displays the
list of computers, shared folders, and printers; the Computer
Browser service manages this list. Every time Windows NT boots up,
this service also starts.

Computer Browser is responsible for two closely
related services: building a list of available network resources,
and sharing this list with other computers. All Windows NT
computers run the Computer Browser service, but not all of them are
responsible for building the list.

Most computers will only retrieve the list from
the computers that actually collect the data and build it. Windows
NT computers can therefore have different roles. Let’s take a look
at them:

  • Domain master browser: In NT domains, the primary domain
    controllers (PDCs) handle this role. The PDCs maintain a list of
    all available network servers located on all subnets in the domain.
    They get the list for each subnet from the master browser for that
    subnet. On networks that have only one subnet, the PDC handles both
    the domain master browser and the master browser roles.
  • Master browsers: Computers maintaining this role build the
    browse list for servers on their own subnet and forward the list to
    the domain master browser and the backup browsers on its own
    subnet. There is one master browser per subnet.
  • Backup browsers: These computers distribute the list of
    available servers from master browsers and send them to individual
    computers requesting the information. For example, when you open
    Network Neighborhood, your computer contacts the backup browser and
    requests the list of all available servers.
  • Potential browsers: Some computers don’t currently maintain
    the browse list, but they’re capable of doing so if necessary,
    which designates them as potential browsers. If one of the existing
    browsers fails, potential browsers can take over.
  • Nonbrowsers: These are computers that aren’t capable of
    maintaining and distributing a browse list.