Client Operating Systems

• Identify the basic capabilities of client workstations (i.e., client connectivity, local security mechanisms, and authentication).

Whereas a network operating system works behind the scenes, providing the services that make the network function, the workstation operating systems act as the window to the network. For that reason, network administrators must be aware of the operating systems that grace the front end of the network.

As stated previously, Microsoft's Windows products dominate the desktop operating systems market. The other operating systems discussed in this chapter hold single-figure percentages of the market share. However, these other systems are readily available, and their numbers are growing.

Windows 95, Windows 98, and Windows Me

Perhaps the most widely used client operating systems are the Windows-based clients, Windows 95, Windows 98, and Windows Me. These clients are used in network environments of all sizes, ranging from small office and home office environments to large corporations. Their popularity can be attributed to the familiar, easy-to-navigate graphical interfaces, compatibility with most of the current popular applications, and their low cost, at least in comparison to other Windows products, such as Windows NT Workstation and Windows 2000 Professional.

Application Support for Windows 95, Windows 98, and Windows Me

Windows 95, Windows 98, and Windows Me systems support all but a few of the major applications used today. They were designed to be used with office productivity tools such as spreadsheets and word processors. In addition, they support a range of entertainment applications. Of all the operating systems in use today, they have the greatest commercial software support.

Local Security Mechanisms for Windows 95, Windows 98, and Windows Me

If there is one failing in Windows 95, Windows 98, and Windows Me–based clients, it is their local security. Windows clients have no file system security, which means that the files you save on your system can be accessed by anyone who uses your computer. There are third-party products designed to either hide folders and files or password-protect them.

Windows 95, Windows 98, and Windows Me clients also do not provide a mechanism to prevent tampering with systems and application settings. Perhaps even more significantly, anyone can use a Windows 95, Windows 98, and Windows Me system without providing a username and password.

The lack of a local security mechanism makes Windows 95, Windows 98, and Windows Me clients an unsuitable operating system for many network environments and for particular categories of users on a network. If local security is required, an operating system such as Windows NT or 2000 should be used.

Authentication for Windows 95, Windows 98, and Windows Me

Windows 95, Windows 98, and Windows Me clients require a username-and-password combination in order for users to log on to the network and access network resources. The system is then authenticated by the server that is being used. Authentication is a function of the server operating system rather than the local workstation.

Windows NT Workstation, Windows 2000 Professional, and Windows XP Professional

Windows NT Workstation, Windows 2000, and Windows XP Professional were introduced to provide robust, secure, high-performance alternatives to Microsoft's other workstation operating systems, such as Windows 95, Windows 98, and Windows Me. Since the introduction of Windows NT Workstation as a business-oriented operating system, Microsoft has succeeded it with two other versions: Windows 2000 Professional and its latest offering, Windows XP Professional. Built on the same basic building blocks as Windows NT Server, these products are popular in corporate environments where local workstation security is as important as the security of the server. Windows NT Workstation, Windows 2000, and Windows XP Professional use the same authentication mechanisms as their corresponding server products, and they support NTFS for file system security.

Application Support for Windows NT Workstation, Windows 2000 Professional, and Windows XP Professional

Application support for Windows NT Workstation, Windows 2000, and Windows XP Professional Workstation is very high, although certain applications are simply not supported. All the operating systems discussed in this chapter have the ability to support DOS applications and 16-bit and 32-bit Windows applications, as well as some other platforms. In general, this compatibility works flawlessly, although certain applications can cause problems. One such problem is that any application that interfaces directly with hardware won't work. This is because Windows NT Workstation, Windows 2000, and Windows XP Professional have a special set of drivers that intercept calls made to the hardware. Only applications that understand the function of these drivers and know how to interface with them can be used on these systems.

Client Connectivity for Windows NT Workstation, Windows 2000 Professional, and Windows XP Professional

Windows NT Workstation, Windows 2000, and Windows XP Professional are intended to be suitable clients for any of the common network operating systems. To connect to NetWare servers, Microsoft provides CSNW, although Novell offers client software that has more functionality. To connect to a Linux server running Samba, no additional software is required.

Local Security Mechanisms for Windows NT Workstation, Windows 2000 Professional, and Windows XP Professional

Windows NT Workstation, Windows 2000, and Windows XP Professional share the same security subsystem as their server counterparts and use the same security mechanisms. User accounts can be defined locally on the workstation, or the system can be made a member of a domain, in which case user accounts from the central user account database can be used to log on to the workstation and therefore the domain as well.

Authentication for Windows NT Workstation, Windows 2000 Professional, and Windows XP Professional

Two pieces of information are required to log on to a Windows NT or Windows 2000 system: a username and a password. Of the two, the username is not case-sensitive, but the password is. If the workstation has also been made a member of the domain, an additional dialog box allows you to specify whether you want to log on as an account from the local workstation or as a user account from the domain.

Linux

Although Linux has not experienced the same success as a workstation operating system as it has at the server level, it is increasingly being looked to as an alternative to the other offerings. Many Linux distributions actually include a “workstation” option that can be selected during the installation process. Instead of installing server-type applications (proxy server, Web server, and so on), the installation focuses on workstation-type applications and utilities.

Applications for Linux

One of the myths that has traditionally surrounded Linux is the lack of applications that have been written for it. In the early stages of Linux, this might have been true, but it is certainly no longer the case. The range and quality of applications and utilities available for Linux is truly impressive.

As the popularity of Linux has increased, so has the number of software companies developing Linux-friendly applications. One of the most high profile of these companies is Corel, which has developed a WordPerfect Office suite for Linux. Commercially available software for Linux is licensed in the same way as the software for other operating systems: You need a license to install the product, and you do not receive the source code for the program.

In addition to commercially available software, there is also a larger amount of “free” Linux software. For every commercially available Linux software package, there is an equivalent that is available free of charge. A good example of free software is StarOffice, which is an office suite from Sun Microsystems that includes a spreadsheet, word processor, and all the productivity tools required by desktop users. Free Linux software does not end there. You can get firewall software, proxy software, and backup software—just about any software you need to use Linux as a server or desktop solution.

Client Connectivity for Linux

In either a server or client configuration, Linux supports many networking protocols, giving it the capability to operate as a client in many network environments. The latest versions of Linux include support for TCP/IP, IPX/SPX, and other protocols. This allows Linux clients to interoperate with common network operating systems, although you might need to install client software on either the client or the server to facilitate connectivity.

In NetWare 6, native file access makes it possible for Linux clients to access NetWare server resources without additional software.

Local Security Mechanisms for Linux

Linux is an inherently secure operating system, although the system administrator might need to have a detailed understanding of the operating system to make it completely bulletproof. For local security measures, a username and password combination is required to log on to the system, providing the basis of user verification. In the past, username and password information was stored in a plain-text format, which constitutes a security risk. Today, it is far more common to use the password shadowing technique discussed earlier in this chapter, in the section “Linux User Management Basics.”

For file system security, the EXT2 file system, and others, can be used to secure the files that are held on a system.

Note that unlike Windows systems, where there are differences in the security measures and mechanisms from version to version, a Linux system used as a workstation and a Linux system used as a server utilizes the same underlying operating system. Therefore, the information provided earlier about security on Linux servers is equally applicable to Linux clients.

Authentication for Linux

Linux authentication is based on a username and password combination. Without a valid user ID, it is very difficult to access a local system. Of important note is that on a Linux system, there is a root account that can be authenticated on any system. The root account is comparable to the Administrator account on Windows networks. On a Linux system, both the username and password are case sensitive.

Macintosh

Since its introduction, Macintosh has supplied network connectivity features including hardware as well as protocols to facilitate communications. Early systems included a networking interface called a LocalTalk adapter. Networking functionality was also built in to the operating system, using AppleTalk (discussed in Chapter 5, “Overview of Network Protocols”) as the protocol suite.

Although today's Macintosh computers might look very different from those early systems, their networking legacy remains intact. A Macintosh makes a great client for all the common network operating systems. However, depending on the type and version of network operating system and MAC OS being used, additional software might be required at either the server end or the client end.

Application Support for Macintosh

There is no shortage of software for Macintosh computers. In fact, many of the programs Windows users have come to know and love were first written for the Macintosh and, according to Macintosh users, worked better on Macintosh than they do on Windows. Some areas of particular software strength for Macintosh computers include graphical and desktop publishing applications and educational programs.

In addition, Macintosh systems can use Windows applications by using a process called emulation. This allows Windows-based programs to run on Macintosh, but there are performance losses, and in some cases, the programs won't run at all.

Client Connectivity for Macintosh

Macintosh computers make suitable clients for most network operating systems, but in some cases, there is a need for additional software. For example, to connect to a NetWare server, special client software is required. NetWare now includes native file access that can allow Macintosh clients to access a NetWare file system without additional software. For Windows NT/2000 servers, a product called Services for Macintosh can be installed; this product makes selected shares and printers available to Macintosh clients.