If the NOS makes a computer a server, what makes a computer a network client? For communication to take place between a network client and the network server, client computers must also be outfitted with software that "tunes" them to the network. This software is aptly called network client software .
When a standalone computer accesses a file on the local hard drive or prints to a directly connected local printer, this request for service goes to the computer's processor. The processor then makes this request a reality and either opens the specified file or sends a print job to the printer. All this activity is managed locally.
So, how do computers that are designed to access resources locally suddenly become able to access shares on a file server or print to a remote printer on a print server? The network client software that is installed on the client computer actually performs a little "bait and switch" operation that makes the computer think the network resource is still just a local resource.
This process is handled by a part of the network client software called the redirector . The redirector intercepts any requests made on the computer, such as a request to open a particular file or to print to a printer. If the redirector finds that the user wants to access a remote file on a server or print to a network printer, the request is forwarded to the network server. If the request is for the access of a local file (on the computer's hard drive), the redirector allows the request to proceed to the computer's processor so that the request can be processed locally.
The redirector can also forward requests from a client machine to servers that supply resources, such as network shares (or shared folders, which are discussed in the next chapter), or servers that supply print services (on small or medium-size networks, this might be handled by just one network server). Requests made on the client computer for remote resources are handled by the network operating system on the server.
Figure 7.1 supplies a diagram of how the redirector directs requests to either the local processor or the network server. The client computer is fooled by the redirector into thinking that all the resources it accesses (whether local or remote) are local.
Figure 7.1. The redirector on the client computer determines how requests for services should be routed.
Configuring Network Clients
For a computer to log on to a particular network type, it must be configured with the appropriate network client software. Microsoft Windows provides the necessary clients for both networking on a Microsoft network and a NetWare network. Figure 7.2 shows the Connection Properties dialog box for a computer running Windows XP Professional. Notice that both the Novell Client for Windows and the Client for Microsoft Networks have been installed on this computer.
Figure 7.2. Network client software allows a client to communicate with the network server.
It is not only necessary to have the correct client running on the computer, but it is also a good idea to keep the client up to date. For example, although Windows provides a Novell client (from Microsoft), a more recent client will probably be available on the Novell NetWare site. It can then be downloaded and installed on your network clients.
Client software provided by an NOS vendor such as Novell will also often include utilities that make it easier for the client to navigate the network and network resources. For example, the Novell client (at least the latest when this book was being written) provides the NetWare Connections utility, which allows a user on a client computer to check connections to various servers on the network. The Network Connections utility, shown in Figure 7.3, is launched by right-clicking the NetWare Services icon in the system tray. This icon is placed there when you install the NetWare client software on a Windows-based computer.
Figure 7.3. Network client software will often include utilities that make it easier for users to view and access network resources.
Configuring Client Computers with LAN Protocols
The network client computers must also be configured with at least one of the network protocols supported by the network server. If you are running a TCP/IP network, both the server and the network clients must be configured for TCP/IP. If you are running clients in a mixed network environment, where resource servers may be running different network operating systems (such as Windows 2000 Server and NetWare, which is discussed in the next chapter), the clients must be configured with all the necessary protocols.
Configuring LAN protocols on a Windows-based client is very straightforward. For example, protocols are added on a Windows XP client from the network connection Properties dialog box. You click the Install button and the Select Network Component Type dialog box opens (see Figure 7.4). You then select Protocol to see a listing of available protocols that can be added to the computer's configuration.
Figure 7.4. You can add protocols to the client's configuration.
Once a client computer has been configured with the appropriate network client and with the needed LAN protocols, that client computer can be connected to the network. All a user will have to do is turn on the computer and then provide an appropriate username and password to log on to the network.