ExamSim For MCSE 2000:Question 3 - Missing Browse List Entries Page 2

Thomas Shinder

The correct answer is B.

This question is typical of the type of questions that you'll see on your Microsoft exams. It tests your understanding of multiple concepts, and you ability to integrate your understanding of these concepts to come up with the correct answer.

The Browser service is a distributed database that contains a list of all the servers on a Microsoft network. In the context of the Browser service, a "server" is a machine that is running the server service. It is not a Windows NT or Windows 2000 Server computer. This means that any Windows based computer can be a server - all it needs to be a server that will show up on the Browse List is to be running the server service.

On a TCP/IP based network, each network segment will have a single Master Browser, which is selected via a process known as a Browser Election. In general, the machine with the newest and most powerful Windows based operating system will take the role of the Master Browser for its segment. There are ways of insuring that a particular server is the Master Browser by editing the registry and adding the IsMasterBrowser entry into the registry.

When network clients running the server service start up on an IP segment, they issue a server announcement, which is via a UDP broadcast packet. Since routers typically are not configured to pass these broadcast packets, these connectionless UDP broadcasts are limited to the segment on which they are issued. The Master Browser on the segment listens for these server announcements, and places the names of the computers that issue these broadcasts onto the Browse List. The Master Browser collects this information over time and is able to collect a complete list of servers on its segment.

In order to get a complete list of servers on all IP network segments, there must be a mechanism in place that will allow all the Master Browsers from all the segments to share what they know about their own segments with the other Master Browsers. In order to accomplish this, you need a Domain Master Browser. Each segment's Master Browser reports to the Domain Master Browser and sends to it the list of servers from its own segment. The Domain Master Browser is able to collect the information about the servers located on each IP segment on the network, and then returns this information to each of the segment Master Browsers located on the network.

On a Windows NT network, the Domain Master Browser is the Primary Domain Controller. On a Windows 2000 network, the Domain Master Browser will be the PDC Emulator.

There must also be a method in place that allows the segment Master Browsers to find the Domain Master Browser in order for them to report to it. The most common and efficient mechanism is to use a WINS Server. When the Domain Master Browser registers its NetBIOS Names with its WINS Server, one of the names it registers is its domain name with the [1Bh] service identifier. When segment Master Browsers are configured to query a WINS Server for NetBIOS names, it will query the WINS Server for the [1Bh] record for its domain and then contact that IP address. This is how the segment master browser is able to find and communicate with the Domain Master Browser.

The Browser Service is a NetBIOS dependent service, and is an unfortunate legacy left over from the history of Microsoft networking. All network operating systems that Microsoft has put out, prior to Windows 2000, were dependent on NetBIOS, and the NetBIOS interface on TCP/IP based networks. However, Windows 2000 is not NetBIOS dependent, and because network resources can be published in the Active Directory, there is no longer any compelling reason to have the broadcast based Browser Service enabled on your network.

For an explanation of each of the answers, check out the next page.

This article was originally published on Nov 27, 2000
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