The information that Windows machines
display in the Network Neighborhood and in other places where you can
pick a computer from a list comes from a server known as the Windows
Browser. This is a separate service from name resolution and is not
just dependent on name resolution, but also intertwined with it. In
particular, machines use special names to locate Browser servers, and
those names are sometimes registered and resolved exceptionally. The
Browser service is responsible for most of the mysterious broadcast
packets to port 138 that you will see on Windows networks, and a
significant number of the mysterious headaches suffered by Windows
administrators. The headaches are greatly magnified by the fact that
very few people understand exactly what Browser service is supposed
to do, let alone how it does it.
The Browser service is responsible only for maintaining lists of
computers so that human beings can pick them from the list instead of
having to be able to type the computer's name. The Browser does
not list the resources actually available on the computer; it
isn't part of WINS, much less the same thing as WINS; and it
isn't involved in any direct interactions between servers and
clients. It's not at all unusual for a machine to be visible
via the Browser but not actually accessible, and this is not a
problem with the Browser. If it is accessible but unintentionally
invisible, that's a Browser problem but not a surprise.
Originally, Windows Browser service was entirely broadcast-based. A
number of complicated changes have been made to allow it to work
across routers, so that in theory if a network stays the same for
long enough, and contains enough Windows NT machines, browsing
information will stabilize and propagate across the entire network.
For a complex network, this process may take a considerable amount of
time and in fact will often take longer than the average delay
between network changes.