The term "Windows networking" refers to any system that has a native client or server function that will work with Windows 3.1, Windows for Workgroups, Windows 95, Windows NT, and DOS. It is based on a set of rules developed by Microsoft and modified as the need has arisen. There are specific functions, features, and quirks that are unique to the networking world. All of the networking functions are controlled by the Registry when you are working with Windows 95 and Windows NT.
The basic concept of networking is that you share expensive devices and data among several people to reduce cost and increase efficiency. The management of the devices was discussed in earlier chapters. All of the sharing of the devices and data and the management of the traffic are dependent on the Registry and will be covered in Chapters 18 through 21. For example, when you share a folder or printer in Windows 95 or NT, it stores the share information in HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanmanServer\Shares. If that information is changed in the Registry, or if the Registry becomes corrupted, the nature of the share will change.
In order for a system to be able to work on a network, it must have several components installed. For all but NT Server, these are optional items. Though they come with the software, you do not have to install them to make the software work. You would only install the networking components to get network capabilities on the system. Windows NT Server will not install if the following networking components are not installed:
When you install these components, pointers are set in the Registry for locations of files, settings are set for the configuration of those files, and networking services are installed.
Data that transfers from one computer to another is controlled by software and settings that adhere to rules called the OSI model. OSI (Open Systems Interconnection) was developed in 1977 so computers could easily talk with one another, and a set of rules was given to all manufacturers to ease the interconnection. It's a complex set of rules, but the bottom line is that all data that needs to get from one computer to another uses many layers of functions to get there.
Microsoft uses the OSI model as the foundation for its NDIS driver functions. OSI sets the standards, and then other companies determine how those will actually be implemented in their network tools. Novell has its own opinions about how the OSI model should be implemented, and they have done that in their own client software and drivers. Microsoft has chosen a different path for its NDIS drivers and the Windows networking client. Sun has also chosen a different path.
The key to making networking work in a cross-platform setting is that, eventually, the data gets to a format that can be transferred from one card to another. There can be no worry about how one 10BASE-2 Ethernet card will transfer information to another.
Figure 17.1 is a simplified model that shows the layers of steps that data has to go through to get from one user to another.
Figure 17.1. Layers of steps for data transfer on a network.
Every layer has settings,
which are held in the Registry. Every layer adds information
based on those settings to the actual data that goes across the network. When that
information is received on the other end, it tells the receiving computer how to
deal with the data.
If any of the data that the computer sends across the network is incomplete or incorrect, the data transmission will not be complete, and errors will occur.
Most of the time, the error messages will tell you that the data did not transfer, and you will need to investigate to determine the reason. The error could be practically anywhere in the settings.
Troubleshooting a network and determining the causes of a misconnection reminds me of the "Man of a Thousand Disguises." There are so many variables that the errors you receive may point to dozens of potential problems. For more network troubleshooting with the Registry, see Chapter 20, "Troubleshooting and Configuring Networking Registry Settings."
Working as a server means that you share access to your disk drives, printers, and other devices with other users who connect with your system. The user will not have access to items that you have not shared. Users can connect to you through network cabling, modem, or other transmission opportunities such as radio waves, microwave relay, or direct digital connection.
In order to set up a system to work as a server on the network, it needs to have a network card or other connection device enabled. A network card is inserted, and the system needs a driver. This file, or set of files, controls the physical access into and out of the card. Normal settings include IRQ and I/O port address settings. Those settings must be unique inside the PC, or conflicts will keep the system from transferring information to or from the card.
The driver information and settings will be stored in HKEY_LOCAL_MACHINE\Enum for Windows 95 systems and in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services for Windows NT.
For example, you have installed a network card in your NT system with the IRQ set to 10 and the I/O port address set to 300 with jumpers on the card. When you install the card driver in Windows, you would use the same settings. After completion of the driver setup, you close the Network Control Panel applet, and you will be prompted to restart the system. When you restart, you try to find the server, but you cannot log onto the domain because the system says there is no machine with that name on the network.
Normally, you would then check the cable and the domain name to see if the card was started. If the driver loaded, the card must have been able to be seen by the system. This indicates that the I/O port address is not the problem. If the I/O port address was in conflict, the card driver would not have loaded, and you would have gotten an error in the Event Viewer.
Because the driver loaded, the I/O port address is OK, and the system thinks there is a network. The IRQ is the setting that allows the system to communicate with the network card. With an incorrect IRQ, the driver loads, but there are no systems on the network, not even yours. Not being able to see any systems on the network is indicative of an IRQ problem. You then need to use another IRQ setting that is not in use by any other card in the system. If you can see your system, but no others, that may be a connection problem.
The other part of the server function that is critical in the server settings is the computer name. All access to shares is through a name in a UNC (Universal Naming Conventions) format. A share called LASER1 on a system named SERVER1 would be listed as \\SERVER1\LASER1. The name for the computer, the names of the shares, and all of the settings for the shares are in the Registry.
Just as the server functions need a network card/connection device, the client also requires one. All of the settings for the card and the driver are in exactly the same locations as they would be for a machine acting as a server. Most systems can act as both.
In addition to the device entries, the client computer must also have a redirector. To connect to a Windows NT, Windows 95, or Workgroups machine, you must have the Microsoft client. To connect to a NetWare server, you would need a NetWare client. You can get that client software from Microsoft or from Novell. Either way, the settings for the client are in the Registry. Client software is also available that can be added to Windows 95 and Windows NT to allow them to connect to Banyan VINES, UNIX, AS/400, and other network servers.
The three standard protocols are TCP/IP, NetBEUI, and NWLink (IPX/SPX). All three are supported in Windows networking, and in 95 and NT they can all be present at the same time. The computer needs information about each protocol so the computers can talk to each other.
In terms of the settings the user needs to make, NetBEUI is the simplest protocol. Some people wrongly assume that there are no settings in the Registry for NetBEUI. There are several, but they are configured automatically, and the user does not need to set any of them. In the Registry, NetBEUI settings are in keys with an NBF designator.
The next protocol, in order of difficulty of setup, is NWLink. NWLink is Microsoft's implementation of Novell's IPX/SPX protocol. It is the most commonly used protocol in local area networks, because of Novell's dominance in the market. NWLink is also automatically configured to defaults, and for most networks, that is enough. Occasionally, there is a need to modify the settings for a more advanced or complicated networking environment. All of the settings for NWLink in the Registry use the NwlnkIpx label.
TCP/IP is the most difficult and most configurable of the protocols. It is commonly used as the protocol to connect different types of systems together so they can transfer information. Because TCP/IP has so many items that need to be set, it is very easy to make a little mistake that will keep the systems from communicating with each other. In the Registry, all generic TCP/IP protocol settings will be under the Tcpip key, and all card-specific settings will have the NetBT label.
Every network has the ability to implement security features. How much security you implement and enforce depends on the number of people on the network, how much of a security risk the people are, and how sensitive the data is on the network.
Security features in the Registry are in many different locations. In Windows NT, there is a complete hive for just security settings that can be implemented through NTFS security, and another that holds all the user names, passwords, and access rights. They are not accessible through the Registry editors, but all of the data is managed through the Registry.
Other security features are based on the interface, logon, and information stored in easily accessible locations. By changing the settings in the Registry, you limit access and reduce your risk exposure. Individually, the settings may not create a positive security environment, but together, they can lock down the network and make it very difficult to penetrate.
The Registry is an integral part of making networking work in Windows 95 and Windows NT. The settings for all the devices, protocols, redirectors, and shares are stored in the Registry. By making sure that the information for each part is correct, you can make the whole network work. It may be tedious to ensure that all the settings are correct, but it is the only way to isolate problems in the Registry associated with networking.
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