In a Microsoft network, the following events take place when member computers are turned on.
When they are turned on, all computers announce their presence to the master browser in their workgroup or domain, even if they don’t have shared resources to advertise.
The first time a client computer attempts to locate available network resources, it looks for a master browser using a QueryBrowserServers broadcast.
The master browser for the domain or workgroup sends back a list of backup browsers. The client caches up to three backup browser names in its memory and uses one of those to find out about network resources when necessary.
When it needs a resource, the client sends a NetServerEnum2 API call to the backup browser.
Special Note: Because the client chooses the backup browser randomly, it is possible that the client won’t see all the available resources. The backup browsers update their lists from the master browser once every 15 minutes. Any computers that have been turned on between updates may not be visible on the browse list. To force an update of a browse list, you can use these commands from the command prompt on the browser computer :
NET STOP BROWSER
NET START BROWSER
Rebooting the browser computer has the same effect but you may not want to do that. Note that you can run these commands remotely using the methods described in Chapter 4. Also, there are a number of NT Resource Kit utilities that let you to manage browsers and obtain detailed status information about the browsers in your network.
The backup browser responds to the requesting client with a list of domains and workgroups and the list of servers local to the client’s domain or workgroup.
The user at the client selects either a local server, a domain, or workgroup to view available servers. For example, when we use a NET VIEW command on a small test network with two domains — one called Foretell and the other called FTL — we get the following results:
NET VIEW
Server Name Remark
------------------------------------------------
\\FTL40
\\SBS01
\\TOSHNT
The command completes successfully and shows the servers on the network. By running the command again, this time with a specific server name, we receive the information shown in Figure 5.2.
At times, you may not want your computer to announce itself to master browsers. To hide a computer from browsers, add a value named Hidden to the following Registry key:
Select the Data Type as REG_DWORD and type 1 as the value. Changing this value hides the computer’s resources from the browsers. Please note that these changes are made to the LanManServer key and not to the Browser key in the Registry.
You can also hide a computer’s resources using the following command at the command prompt:
NET CONFIG SERVER /HIDDEN : YES
Now, when you use the NET VIEW command, you won’t see the workstation or server in the browse lists. It may take a while (anywhere from 15 to 51 minutes) for this change to be propagated throughout the domain.
Special Note: The Hidden Registry value is not visible by default. NT tries to save string space by not including some of the defaults in the Registry. This economy carries an unexpected side effect, however. When you use NET CONFIG commands to change Registry settings for values not explicitly visible in the Registry, NT then apparently assumes that you know what you are doing and makes visible a number of other Registry entries. After they are visible, NT no longer automatically makes appropriate changes to these values. As a result, if you change the configuration — for instance, if you change the network configuration, such as adding more memory or adding multiple network cards — NT no longer automatically adjusts the settings in the Registry for the LanManServer key. For this reason, we recommend editing the Registry instead of using the NET CONFIG commands.
VIEWING AND MONITORING BROWSERS
The NT Resource Kit is an excellent source of network diagnostic tools, including the BROWSTAT utility, which you can use to look at browsers on your network.
Tip: An economical way of obtaining the NT Resource Kit(s) is through a TechNet CD subscription. With the subscription, you receive a set of CDs every month that contain product documentation, resource kits for all the Microsoft products, and knowledge base articles. For further information, visit http://www.microsoft.com/technet.
To use the BROWSTAT utility, simply type BROWSTAT and the appropriate command from Table 5.1 on any NT computer on the network. It returns information about the browsers in the same domain as the computer on which you type the command.
The listing in Figure 5.3 shows the results of a BROWSTAT STATUS command run on the small test network we used previously. The command was run from a computer in the FTL domain.
To view browsers on any domain on the network, follow the command with the domain name. BROWSTAT STATUS FTL produces the same result as above because the computer on which this command was run is a member of the FTL domain.
BROWSTAT STATUS FORETELL produces the result in Figure 5.4.
You can use the BROWSTAT utility to discover browsers for each transport used in a domain. For example, the command
All three computers listed in Figure 5.5 are NT 4.0 computers running Workstation (W) and Server (S) services. FTL40 is an NT Server set up as a standalone server (SS) and is a Potential Browser (PBR). SBS01 is a PDC (PDC), print queue server (PQ), and master browser (MBR). TOSHNT is an NT Workstation that acts as the backup browser (BBR) and is also a potential browser. (Table 5.2 lists all the flags that can appear in server or domain list displays.)
From a browser’s perspective, standalone servers and NT Workstations are pretty much the same. In the example in Figure 5.5, the NT Workstation (TOSHNT) takes on the role of backup browser instead of the NT Server because it has the longest uptime. If the FTL40 computer were installed as a BDC, it would automatically take on the role of a backup browser. The general relationships among browsers, domains, networks, and domain controllers are shown in Figure 5.6.
Browsers may be monitored with BROWMON, a graphical tool from the NT Resource Kit. BROWMON doesn’t have to be installed on the computer you’re working from; you can run it from anywhere on the network.
If you have installed the NT Resource Kit on your local machine, go to Start, Resource Kit 4.0, Diagnostics, Browser Monitor. If you are accessing this utility from a network share, just type BROWMON at the command prompt. After you see the initial screen, go to Domain and Add Domain. In the example shown in Figure 5.7, the two domains FORETELL and FTL have been added to the list.
Double-clicking FTL gives us the information shown in Figure 5.8.
The network has two browsers (SBS01 and TOSHNT), three servers (FTL40, SBS01, and TOSHNT), and two domains (FORETELL and FTL). Although the black-and-white image doesn’t show it, the SBS01 icon is red to indicate that SBS01 is the master browser.
You can select a browser and click Info for further information (Figure 5.9).
The command BROWSTAT STATUS \\SBS01 gives us the same information, and it has the advantage of resetting the counters. Sample output from the BROWSTAT command is shown in Figure 5.10.
The most important of the BROWSTAT statistics are explained in Table 5.3.
For more information about BROWSTAT and the information you can discover with it, see the NT Resource Kit and the Technet CDs.
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