Über die Autorin bzw. den Autor

Doug Lowe is the Information Technology Director for a civil engineering firm in California. He has been managing networks for more than 20 years and has written 50+ technology books, including Networking All-in-One For Dummies, 3rd Edition and PowerPoint 2007 For Dummies.

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Need to build a network or use one? No idea where to start? Start here!

So you want to use a network — or worse, someone wants you to set up one. Here's just what you need to know in a language you can understand, even if you don't own a pocket protector. Find out what a network is, how to take advantage of what it offers, what you need to build and manage one, and how to keep your network (and the stuff on it) safe.

• Just the facts — for users only, here's the scoop on networks, how to use one, and how it makes life easier

• Getting started — find out how to plan a network and what hardware and software you need to set one up

• More techie stuff — what network builders need to know about TCP/IP, DHCP, and DNS

• I'll be your server — learn about setting up a server, configuring Windows clients, and going wireless

• Hooking up — connect your network to the Internet and set up a firewall

• Going mobile — explore the unique factors that affect network access via iPhones, BlackBerry devices, and other smartphones

• Network management — learn to keep your network secure and your users happy

• Those other guys — discover how to network Macs and PCs or set up a Linux network

Open the book and find:

• How to share files, printers, and databases

• An overview of network parts

• Network troubleshooting tips

• What a network administrator has to do

• Security advice for mobile devices on your network

• How to set up an e-mail server

• Advice for a backup plan

• Basic network maintenance tips

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Networking For Dummies

John Wiley & Sons

Chapter One

In This Chapter

* Getting a handle on networks

* Considering why networking is useful (and is everywhere)

* Telling the difference between servers and clients

* Looking under the hood at the network operating system

* Asking "How does it work when a network works if a network works for me?" (Say what?)

* Assessing how networks change computing life

* Identifying (and offering sympathy to) the network administrator

* Comparing servers to clients: What have they got that you don't got?

Computer networks get a bad rap in the movies. In the Terminator movies, Skynet (a computer network of the future) takes over the planet, builds deadly terminator robots, and sends them back through time to kill everyone unfortunate enough to have the name Sarah Connor. In The Matrix movies, a vast and powerful computer network enslaves humans and keeps them trapped in a simulation of the real world. And in one of Matthew Broderick's first movies, War Games, a computer whiz kid nearly starts World War III by connecting to a Defense Department network and playing the game Global Thermonuclear War.

Fear not. These bad networks exist only in the dreams of science fiction writers. Real-world networks are much more calm and predictable. They don't think for themselves, they can't evolve into something you don't want them to be, and they won't hurt you - even if your name is Sarah Connor.

Now that you're over your fear of networks, you're ready to breeze through this chapter. It's a gentle, even superficial, introduction to computer networks, with a slant toward the concepts that can help you use a computer that's attached to a network. This chapter goes easy on the details; the detailed and boring stuff comes later.

What Is a Network?

A network is nothing more than two or more computers connected by a cable (or in some cases, by radio connection) so that they can exchange information.

Of course, computers can exchange information in ways other than networks. Most of us have used what computer nerds call the sneakernet. That's where you copy a file to a CD or DVD disk or a removable flash drive and then walk the data over to someone else's computer. (The term sneakernet is typical of computer nerds' feeble attempts at humor.)

The whole problem with the sneakernet is that it's slow - plus, it wears a trail in your carpet. One day, some penny-pinching computer geeks discovered that connecting computers with cables was cheaper than replacing the carpet every six months. Thus, the modern computer network was born.

You can create a computer network by hooking together all the computers in your office with cables and using the computer's network interface (an electronic circuit that resides inside your computer and has a special jack on the computer's backside). Then you set up your computer's operating system software to make the network work, and - voil - you have a working network. That's all there is to it.

If you don't want to mess with cables, you can create a wireless network instead. In a wireless network, each computer is equipped with a special wireless network adapter that has little rabbit-ear antennas. Thus, the computers can communicate with each other without the need for cables.

Figure 1-1 shows a typical network with four computers. You can see that all four computers are connected by a network cable to a central network device: the hub. You can also see that Ward's computer has a fancy laser printer attached to it. Because of the network, June, Wally, and the Beaver can also use this laser printer. (Also, you can see that the Beaver stuck yesterday's bubble gum to the back of his computer. Although the bubble gum isn't recommended, it shouldn't adversely affect the network.)

Computer networking has its own strange vocabulary. Although you don't have to know every esoteric networking term, it helps to be acquainted with a few of the basic buzzwords: