Introduction to Network Operating Systems

• Identify the basic capabilities (i.e., client support, interoperability, authentication, file and print services, application support, and security) of the following server operating systems:

  • Unix/Linux

  • NetWare

  • Windows

  • Macintosh

Early network operating systems provided very few network services, such as file and printer sharing. Today's network operating systems offer a far broader range of network services; some of these services are used in almost every network environment and others are used in only a few.

Despite the complexity of operating systems, the basic function and purpose of a network operating system is straightforward: to provide services to the network. Network operating systems provide several services for the client systems on the network. The following are some of the most common of these services:

• Authentication

• File and print services

• Web server services

• Firewall and proxy services

• Dynamic Host Configuration Protocol (DHCP) and Domain Name System (DNS) services

These are just a few of a large number of services that a network operating system can provide. When you take the time to list all the different aspects of network operating systems, you gain an appreciation for their complexity and the many functions they are designed to perform.

Choosing a Network Operating System

When it comes to choosing a network operating system, you have a few choices. A network administrator needs to carefully choose a network operating system according to the needs of the organization. The following network operating systems are used in today's network environments:

• Windows NT/2000/XP/.Net— Windows is the most popular network operating system in use today. With the introduction of Windows XP/.Net, which is both a server platform and a desktop solution, Windows will continue its push to become the network operating system of choice in organizations of all sizes. Many people like the Windows-based network operating systems because of their familiar and easy-to-navigate graphical interfaces, even though these same graphical utilities and menus place increased demands on a server's hardware resources.

• Novell NetWare— Novell NetWare has long been one of the most widely used network operating systems. In the past, NetWare was viewed primarily as a file and print platform, but in reality, it can do much more. NetWare can be implemented in small networks, but it truly shines in a large corporate environment. Novell has lost a great deal of ground to the Windows and Linux platforms, although it still has a solid base of users.

• Unix and Linux— Some people might think that Linux is the new kid on the block, but in fact, Linux has been around for quite some time, and the operating system it is based on, Unix, has been around for decades. Linux is a free, open-source operating system and has found considerable popularity as a server operating system. In addition, although Unix is not free, it has been the network operating system of choice for many large organizations. Be prepared, however; although they are powerful, these network operating systems are not as pretty and graphically intensive as what you might be used to. Working with them requires some command-line input and a better understanding of the underlying technologies than you need when you use some of the other network operating systems.

• Macintosh— Although not nearly as prevalent as the other network operating systems discussed in this list, Macintosh systems can be used in a server role.

Which Network Operating System Is Best?

The debate over which is the best network operating system is an ongoing one, and one that will not be resolved in the pages of this book. All network operating systems have good and bad points, and each provides a solid choice for most modern network environments. Over time, functionality has been added to each of the operating systems, and today, in terms of functionality, there is little difference between these offerings. Similarity in service offerings aside, several points will influence an organization's choice of network operating system. The following are some of the factors you should consider when choosing a network operating system:

• Hardware compatibility— Maintaining a network involves maintaining the hardware on the server. If you intend to use existing hardware in a server, you should verify that the network operating system supports that hardware. Some network operating systems support a wider range of hardware than others, although the best hardware from the mainstream manufacturers is supported by all the major network operating systems. Network operating system manufacturers have a vested interest in supporting the broadest range of hardware possible, and unless you are using some weird and wonderful hardware device, you should not encounter any problems. If you have a selection of unusual hardware, you should ensure that your chosen operating system will support it. Manufacturers publish lists of hardware devices that have been verified as compatible, so be sure to check these lists if you intend to use unusual hardware. These hardware compatibility lists are available on the network operating system vendors' Web sites.

• Technical capabilities— Small organizations often have server administrators who double as teachers, secretaries, or data entry clerks. In environments where a dedicated server administrator is nonexistent and available technical skills are few, choosing the most user-friendly network operating system might be an important consideration. It might be easier for the administrator/data entry clerk to add a new user to a Windows 2000 server from a graphical screen than to enter a cryptic command at a command prompt. The inability of existing personnel to support a product would almost certainly cause more problems than it would cure. There are of course alternatives: Training can bridge the knowledge gap where necessary.

• Application support— Most software manufacturers go to great lengths to ensure that the software they are designing is available to all network operating system platforms. Sometimes, however, a manufacturer cannot or does not ensure that its software will work on every network operating system, so it is important that you check. For example, if your company is using an application database that is not supported by Linux, this would make the installation of a Linux server out of the question.

• Budget— Many choices in IT boil down to the money that is available, and choosing a network operating system is often one such choice. If a Linux server provides all the functionality and services your organization needs and does it for free, why pay for Windows? For those used to paying the price for a desktop operating system, the cost of a network operating system can be quite surprising because it is considerably higher.

• Technical support— An important factor in choosing a network operating system is technical support. Each of network operating system manufacturer offers support for its product(s); however, the cost and the usefulness of this support might not be in line with what you need. One thing is for sure: Support and network management go hand in hand. Of the network operating systems we have discussed, Novell, Microsoft, and Unix have very defined support structures. Linux has a less-well-defined support structure, although some Linux distributors offer very comprehensive technical support programs. Other Linux distributors take a more hands-off approach, leaving you to rely on Internet newsgroups and your own savvy.

Now that we have looked at some of the considerations when selecting a network operating system, we'll take a more detailed look at common NOSs and some of the utilities and procedures associated with them. We will also look at each of the CompTIA-prescribed criteria related to network operating systems:

• Authentication— Authentication is a fundamental security-related consideration for networks. Authentication is essentially the process of verifying the identity of the person trying to access a resource on the system. The most common use of authentication is the logon process, in which a user's identity is validated. A detailed discussion of authentication methods used by the various network operating systems is not required for the Network+ exam; however, a basic knowledge of how each of the network operating systems handles authentication is an asset in real-world network administration.

• File and print services— One of the fundamental and most commonly used network services is file and print services. Each of the network operating systems is fully capable of providing these services to network users, but each provides these services in its own way and with a unique set of features.

• Application support— What applications are supported by a network operating system plays a major part in how the network operating system is used and in its popularity.

• Security— A discussion of network operating system security is difficult to capture in a single chapter. In fact, you will find that there are volumes of books dedicated to discussions on how to establish security and how to work around it. This chapter provides only a brief introduction to the security measures taken in network operating systems. Security is a major consideration on networks, and the skills and strategies needed to properly secure a network against inside and outside threats is one of the most valuable skills for network administrators to have.