Sams Teach Yourself MCSE Windows NT Server 4 in 14 Days
(Publisher: Macmillan Computer Publishing)
Author(s): David Schaer, et al
ISBN: 0672311283
Publication Date: 12/15/97

11.3. Computer Browsing

The browser service enables users to access resources on other computers. However, this traffic is broadcast-based. These broadcasts are not forwarded by routers, so it remains on the local subnet. Accessing resources on other subnets can be accomplished via the WINS server.

A computer will announce itself to the network every 12 minutes whether it has something to share or not. When a client wants to access a remote resource it first requests a list of backup browsers. If this request is not answered, an election packet is then sent, forcing an election.

After the browse list is acquired, the client then selects the server that has the desired resource. As a result, a list of shared resources controlled by that computer is sent to the client. The amount of traffic generated by this process depends on the number of servers and how many resources the selected server has to offer.

The best method for reducing browser traffic is to disable the server service on computers that do not share resources. Not only does this reduce the size of the browse list, but it also reduces the number of announcements sent over the network.

Because all browser announcements are sent over all utilized protocols, reducing the number of protocols also reduces the amount of browser traffic. Configuring your computers by whether they should participate as browsers is a good idea. You can disable the capability to be a browser by setting the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Browser\Parameters\MaintainServerList value to No.

11.4. Windows Internet Name Server (WINS)

You use your network primarily so that users can access and share resources located elsewhere on the network. For that to work, one computer must be able to find another computer on a network. At the lowest level, this is done using media access control (MAC) hardware addresses. Every network interface device in the world is given a unique MAC address by its manufacturing company; this address looks something like 04-00-34-2d-3d-74.

When you use the TCP/IP protocol on your network, all network interface devices are also assigned unique IP addresses. When TCP/IP must transmit a message from one computer to another, it uses IP addresses. A part of the TCP/IP protocol stack known as ARP, or Address Resolution Protocol, resolves the IP address to a MAC hardware address on the transmitting end and from a MAC hardware address back to an IP address on the receiving end.

This is all great for computers that can remember infinite combinations of obscure numbers, but we humans like to call things by name. This solves two problems for us. First, IP addresses are hard to remember. Remembering common names is a much easier task. Second, when a computer moves to a different location on a network, its IP address often changes but its name does not.

Windows Internet Naming Service (WINS) solves this problem by allowing users to refer to computers by their familiar NetBIOS computer names over a TCP/IP network. WINS maintains an up-to-date list of NetBIOS computer names and their respective IP addresses.

WINS can provide naming services only for WINS-enabled clients. Users on or outside of your network who are using different systems will not be able to use WINS to resolve NetBIOS names. For this, DNS may be used. Fortunately, DNS and WINS can be used together.

11.4.1. NetBIOS Over TCP/IP

NetBIOS was originally designed for use on small LANs and relies heavily upon broadcasts. On a small network, when a computer must find another computer by using a NetBIOS name, it broadcasts its request and each computer on the network reads the message to see if they are its intended target. Also, whenever a computer initializes, it sends a broadcast to see if its NetBIOS name is already registered on the network.

The problem with all of this is that broadcasts generally will not pass through routers. Thus, NetBIOS does not perform well on large, segmented networks.

This is where WINS comes in. The WINS server maintains an up-to-date list of each computer on the network containing its NetBIOS name and corresponding IP address. WINS solves the broadcast problem by using directed communications.

Client computers are preconfigured with the IP address of their WINS server. Thus, when the client initializes, it sends its registration message directly to the WINS server, which then checks to see whether the name is already registered. If it is not, the WINS server updates its database.

When a client must locate another computer on the network by its NetBIOS name, the request is sent directly to the WINS server, which in turn sends the IP address of the computer back to the client.

Actually, when an h-node client must resolve a NetBIOS name, it first checks its local cache of names previously resolved. If the name is not found there, it then tries to resolve it from the WINS server. If the WINS server cannot resolve the name, the client tries a broadcast. If that fails, the client then tries the local LMHOSTS file, if any, then the local HOSTS file, if any. If these fail, and if one is available, it finally tries to resolve the name using a DNS server.

11.4.2. Configuring WINS Server

Minimal configuration is required when you set up a WINS server. This configuration consists of setting up replication and entering any needed static entries in the WINS database.

Installing the WINS Server Service

To install the WINS Server service on a Windows NT server, do the following:

1.  Open the Control Panel/Network and select the Services property sheet.

2.  Choose the Add button.

3.  On the list presented, select Microsoft WINS Server and choose OK.

4.  You are asked for the path of the Windows NT Server 4.0 installation CD-ROM. Enter the drive letter of your CD-ROM or choose Browse to select an appropriate location. The installation then takes place.

5.  Choose Close on the Network Control Panel.

6.  If TCP/IP had not already been configured on your computer, the TCP/IP property sheet is displayed, asking you to choose a static IP address, subnet mask, and default gateway for each network adapter interface installed on the computer. After you have done this, choose OK.

After this is finished, the WINS service should be running and will run automatically whenever the computer is started. After installing the WINS server, it is ready to begin its job and little other configuration is required. All you must do is configure the client computers you want to use WINS with the IP address of the WINS server.