How to Install a Wireless LAN

Mar. 3, 2004 -- Editor's Note: PC Magazine has partnered with Wiley Books to create a series of PC Magazine and ExtremeTech books. In PC Magazine's Guide to Home Networking Contributing Editor, networking expert and Crosstalk Communications founder Les Free offers a comprehensive guide to network connectivity in the home. Here, we reproduce his step-by-step primer on one of the most popular, and often most difficult, home networking tasks: installing a functioning wireless network.

You can purchase the complete book online at Amazon.com.

Before You Install

Before you begin to install your wireless network, you should have a good understanding of the capabilities and limitations of your wireless network hardware. In this chapter, I'll guide you through the process of installing and configuring your wireless network.

In this chapter, you'll see how toDetermine the best location for your wireless access pointInstall wireless adapters in desktop and notebook computersSecure your wireless LAN against intruders

You've read the book up to this point, you've gone out and bought everything you need, and you're ready to get started. For most people—myself included—your first inclination is to put the wireless access point or router where it is most convenient, hook it up, and leave it at that.

You can certainly do this, and your network may even work as well as you had hoped. But sometimes the most convenient location for your access point isn't the best location. Walls, wiring, and seemingly innocent nearby objects (including fish tanks, cordless phone base stations, and filing cabinets) can interfere with the signal path between the AP and your wireless laptops. Wireless networks use radio waves to communicate, and those radio waves are subject to the laws of physics. If there is a large metal (or water-filled) object between your AP and your favorite Web-surfing couch, the radio signal simply can't get through. If this happens, you will experience slow, intermittent, or no connection between the laptop and the AP. Unless you absolutely must install your AP in a given location, it is well worth the time and effort to determine the best location for your AP.

To do this, you need to perform what network professionals call a site survey. The survey will help you identify possible problem spots in your wireless coverage area so that you can place your AP in the best-possible location. The Surveying Your Wireless LAN section later in this chapter provides detailed instructions for conducting the survey.

Once you've determined the best place to put your AP, you'll need to decide how to connect the AP to the rest of your equipment. If you are adding a standalone AP to an existing Ethernet LAN, you'll need to run an Ethernet cable from the AP to your existing network switch. If you're installing a combination router/firewall/AP device that will connect to a cable or DSL modem, you can either run an Ethernet cable from the modem to the router, or you can move the modem so that it is close to the router.

Since you'll need to install at least one wireless client adapter to perform your site survey, I'll cover that topic first. In the following sections of this chapter, I'll guide you through installing and configuring the rest of your wireless network.

Installing Wireless Adapters

Each wireless computer on your wireless network must have a wireless adapter installed. As you learned in Chapter 4, wireless adapters are available in a variety of form factors, including PCI cards for desktop PCs, CardBus and PC Cards for laptop PCs, and USB adapters for both desktops and laptops.

There are hundreds of wireless adapters on the market today, so it simply isn't possible to give you detailed installation instructions for each one. But having installed dozens of wireless adapters myself, I can give you some helpful hints and tips that may save you some aggravation or a call to the vendor's tech support hotline. The number-one tip I can give you for all of these adapters is to READ THE INSTRUCTIONS packed with your card!

Note: Many wireless adapters come with driver software that must be installed before you install the hardware. If you install the adapter first, the computer will not have the proper drivers installed. The adapter won't work, and you won't be happy.

In the following sections, I'll describe the basic installation steps required for each type of adapter (PCI, USB, and CardBus). You'll also need to configure the software for your wireless adapter; these steps are the same for all wireless adapters.

PCI Wireless Adapters

PCI wireless adapters used in desktop computers can be difficult to install. You'll need to open your PC's case, identify an available PCI card slot, install the card, and put the case back together. This simple PC surgery is second nature to those of us who work with PCs every day, but if you're squeamish about opening up your computer, you may want to opt for professional installation.

To install a wireless PCI card in your computer, follow these steps:

Read the instructions packed with your card. Most cards require that you install driver software from a CD packed with the card. Some cards require that you install the software before you install the card; others require that the CD be in the drive after you install the card. Install the software if necessary, then shut down your computer. Disconnect the AC power cord from your computer. If you need to move the computer to remove the case, you may have to disconnect the remaining cables.

Remove the case or access door from your computer. Figure 7-1 shows a typical desktop PC with the access door removed.Locate an empty PCI card slot. Figure 7-2 shows two empty PCI card slots.Remove the blank cover from the rear of the PCI slot. Insert the card into the empty slot. Make sure the card is fully seated in the slot. You may have to push down firmly on the card, but you shouldn't have to force it.Replace the screw you removed in Step 4.

Close the case and reconnect the cables.Orient the antenna so that is vertical. See Figure 7-3.Install the driver software (if necessary), and configure the wireless adapter to operate with your wireless network. I'll cover this step in detail in the Configuring Your Wireless Adapter section.

CardBus, PC Card, AND USB Wireless Adapters

CardBus and PC Card adapters are the simplest of all cards to install; you simply plug the card into a vacant slot on your laptop and follow the prompts on the screen.

USB wireless adapters are a good alternative to PCI cards for desktop PCs because they are so simple to install. Some USB adapters include a long cable, so you can position the adapter (and its antenna) away from that jumble of wires behind your PC. Many USB wireless adapters come with a small piece of double-stick tape or Velcro, so you can attach the adapter to the back of your desk. Other USB adapters have no cable at all and are designed to plug directly into the USB port on a laptop computer.

To install a wireless adapter in your computer, follow these steps:

Read the instructions packed with your adapter. Most wireless adapters require that you install driver software from a CD packed with the card before you install the adapter; others install the software after you install the adapter. You may need to reboot the system after you install the driver. For PC Card and CardBus adapters, plug the card into an unused card slot on your laptop. For USB adapters, plug the adapter into an unused USB port on your computer or USB hub. Windows will recognize the adapter and install the proper driver as shown in the next section, Configuring Your Wireless Adapter.

Configuring Your Wireless Adapter

Windows XP contains built-in driver support for many wireless adapters. This feature, called Wireless Zero Configuration, or WZC, makes it possible to install many wireless adapters simply by plugging the adapter into the computer. When Windows recognizes a WZC-compatible adapter, it automatically installs the drivers and attempts to obtain a wireless network connection with no intervention from the user.

The network equipment marketplace is very competitive, so many wireless-equipment makers include additional software with their adapter cards in order to give their product a competitive advantage over other products. This software typically replaces the wireless configuration software that is built into Windows XP.

Before you install your wireless adapter, check the instructions to see if you need to install the additional software before you connect or install the network adapter. Some products—like the one shown in the example that follows—may require that you insert the installation CD after you install the card into the laptop.

For this example, I'll install a wireless adapter card that requires the CD to complete the installation. The basic steps to install this card are as follows:

Power up your computer. If you are using a USB, PC Card, or CardBus adapter, connect the adapter to your computer. The Found New Hardware Wizard appears, as shown in Figure 7-4. Notice the instruction to insert an installation CD if one is included. Unless your installation instructions specify otherwise, select Install the Software Automatically, and click the Next button. Windows searches for the appropriate driver for your wireless adapter. If the proper drivers are already installed on your computer, Windows will automatically use those drivers. If not, Windows will prompt you for the location of the driver software.

In most cases, Windows will locate the correct driver to use with no further intervention from you. If Windows finds more than one possible driver, you may be prompted to choose the proper driver, as shown in Figure 7-5. Examine the drivers closely, using the horizontal scroll bar to see all the details if necessary. Choose the appropriate driver from the list and click Next.

Windows installs the driver software. This normally takes only a few seconds. When the drivers are installed, you'll see the final screen from the Found New Hardware Wizard, as shown in Figure 7-6.

At this point, your wireless adapter is installed and should be functioning correctly. Of course, you won't know if it is actually working until you install your wireless access point—the next step in the installation process. If you need to install more than one wireless adapter, you may want to install the AP next and make sure everything is working, and then go back and install the rest of the wireless adapters.

Installing Your Access Point

Now that you've installed at least one wireless client adapter, it's time to install and configure your access point or wireless router. There are four basic steps in this section, and you may be able to skip one of them:

Survey your wireless LAN to make sure you have good wireless communication between the AP and the clients.Connect your AP or wireless router to the rest of the LAN.Configure your AP and wireless clients.Secure your wireless LAN.

Surveying Your Wireless LAN

Many people think they don't need to do a survey because their wireless AP is rated for several hundred feet indoors. But you're unlikely to get that "several hundred feet" range in your own home unless you live in a big, open space—such as an airplane hangar.

Here in the real world, the actual maximum range of a typical AP in a typical home is about 100 feet—or even less. There are all sorts of things that can conspire to reduce the range of your AP, including wiring and metal studs inside interior walls, refrigerators, filing cabinets, and other large metal objects, fish tanks, microwave ovens, 2.4 GHz cordless telephones, and even your neighbor's wireless LAN!

If you plan to use your portable computer in very close proximity to your wireless AP, you can probably skip the survey and simply install the AP in the most convenient location. As a general rule, if you can see the AP, you can connect to the AP. For more suggestions on positioning your AP, see the "Where to Put the AP" sidebar later in this section.

To perform your site survey, you'll need a laptop with a wireless network adapter, and a wireless AP or combination AP/router. Don't have a laptop? If you plan to link several desktop PCs with a wireless network, you still may want to do a site survey first. Instead of moving your desktop PC from room to room, you can simply move the AP to several locations and check the wireless signal quality on each of your wireless desktop PCs. Of course, you'll need to install the wireless adapters in the desktop PCs before you perform the survey.

To perform the survey, follow these steps:

Decide where you would prefer to place the AP, and put the AP in that location.

Plug the AP into a power source so that you can establish a connection to the AP to make sure that your wireless adapter is working correctly. The AP does not need to be connected to your network or broadband modem for this test. Within view of the AP, turn on your wireless client PC. After the system starts up, you should see a message on the lower right-hand corner of the screen, as shown in Figure 7-7. If you don't see this message, your machine is not within range of the AP.

Click on the notification balloon. If the balloon has disappeared, right-click on the network icon (it looks like two computer screens, one in front of the other), and select View Available Wireless Networks. You will see the wireless network connection dialog, shown in Figure 7-8. You should see the name of your wireless network on the screen, under the list of available wireless networks. Select your wireless network, then check the box marked Allow Me to Connect . . . and click the Connect button.Note: If one of your neighbors has a wireless network, you may see more than one network in the list of wireless networks. Right-click on the network icon on the taskbar, and select Status from the pop-up menu. You'll see a display like the one shown in Figure 7-9.

Move your computer around the house while monitoring the speed and signal strength indicators on the wireless connection status screen. Be sure to test the signal strength and connection speed at the locations where you are most likely to use your computer. Keep in mind that the signal strength indicator isn't as important as the link speed. If you have one or more desktop computers on your wireless network, check the signal strength and connection speed on each desktop. If you are satisfied with the coverage area, signal strength, and link speed, you're finished with the survey, and you can move on to the next section. If not, move the AP to another location and repeat the survey.

Where to Put the AP?

If you encounter problems finding a spot for your AP, some of the tips here may help. Many access points can be mounted on a wall. While an AP isn't the most attractive thing you can hang on your wall, you may find that you'll get better coverage from your AP by mounting it up high, clear of your furniture and other obstructions. If you don't want to wall-mount your AP, you can also place it on a high shelf, or on top of a tall piece of furniture.The best place to put your wireless router is as close as possible to the center of the area that you want to cover. The weakest signal area is located directly above and below the AP. Keep this in mind if you live in a multistory home.Keep your AP's antenna(s) vertical if possible. Don't put your AP near large metal objects like metal filing cabinets and desks. Try to keep your AP as far as possible from microwave ovens and 2.4 GHz telephone base units. These products operate intermittently but can cause severe interference when they are in use. Avoid large, water-filled objects like fish tanks and water heaters. Keep the AP away from exterior walls. If you want your wireless LAN to cover part of the outside area of your home, place the AP close to a window.

Connecting and Configuring the Access Point?

Once you've determined the best location for your AP, you're ready to connect the AP to the rest of your network. If you are adding a wireless AP to an existing Ethernet network, you'll need to connect an Ethernet cable from the AP to an unused port on your Ethernet switch. If you are installing a combination AP/router, you'll also need to connect an Ethernet cable from your cable or DSL modem to the router.

Note: The examples in this section show how to configure a standalone access point. If you are installing a combination AP/router device, the procedure will be similar to the example shown here but will include one or two additional steps. I'll cover those additional steps in Chapter 9, so you may want to read both chapters first.

Virtually all wireless access points feature a browser-based configuration wizard. To configure the router, you start your Web browser, enter the IP address of the access point, and answer a few questions. The D-Link AP in the following example uses this approach.

Some access points come with a configuration program on a CD-ROM. To configure these products, you install the configuration program, which walks you through the steps required to configure your AP.

In either case, the steps required are very similar. The following example shows the steps required to configure a D-Link access point using the Web browser interface.

Before you can configure the AP, you must establish a connection from your PC's Web browser to the AP's browser interface. In most cases, the AP will come from the factory set for a specific IP address, usually in the 192.168.x.x private address range. You'll need to start your browser and enter the IP address of the AP in the address bar, as shown in Figure 7-10.

As you can see in Figure 7-10, the browser interface has a button marked Run Wizard that starts the setup wizard. The wizard walks you through the configuration. Figure 7-11 shows the first step in the setup wizard.

The first step is to set a password for your AP, as shown in Figure 7-12. I strongly recommend that you change the password from the factory's default setting. If you leave the AP set with the default password, it is very easy for someone to break into your wireless network and change your network settings. Use a password with a mix of alphabetic and numeric characters.

The next step is to set a name (called an SSID) and a channel number for your AP, as shown in Figure 7-13. The SSID name can be anything you like. For security reasons, I suggest that you not use your family name or house address as part of the SSID.

You can set your AP to one of 11 channels. Virtually all APs come from the factory set to operate on channel 6. If you experience interference from a nearby AP at a neighbor's home, set your AP to channel 1 or channel 11. If you are planning to install a second AP in your home, set one AP for channel 1 or 6, and the other for 6 or 11. Do not set both APs to the use the same channel.

Next, you can enable your AP's encryption security feature. For the time being, I recommend that you leave encryption turned off until you have installed and configured all of the wireless PCs on your network. I'll cover encryption at the end of this chapter. Figure 7-14 shows the encryption settings screen for the D-Link router.

The final step (shown in Figure 7-15) is to accept the settings you have just changed and apply them to the AP. In most cases, the AP will need to reset itself, and you will momentarily lose the connection between the AP and your wireless PC. If you changed the SSID setting, you will need to reconfigure your wireless PCs to use the new SSID setting. If this happens, you will see the "One or more wireless networks are available" message that you saw in Figure 7-8. Click on the message, and then select the new network name from the list and click Connect.

If everything went according to plan, your AP is now configured and operating properly, and you have at least one wireless PC installed and configured to operate with the wireless network. The next step from here depends on your network configuration:If you have more wireless clients to install, this is a good time to install and configure each of them. If you are installing a separate router or a combination AP/router, go on to Chapters 8 and 9, and then come back here and enable the encryption feature on your wireless LAN.

Securing Your Wireless LAN

Wireless networks are very convenient, but they pose a problem for security-conscious users.

Because wireless signals can penetrate through walls and floors, it is possible for anyone with a wireless laptop to connect to your network. Once connected, they can poke around in your shared files, introduce virus or Trojan horse programs onto your network, or send malicious e-mails or spam.

Shortly after the introduction of 802.11b wireless networks, the equipment manufacturers realized that they had a major security problem on their hands. The industry responded by introducing two different types of data encryption for wireless networks: Wired Equivalent Privacy and WiFi Protected Access.

The Wired Equivalent Privacy (WEP) encrypts data using a shared password called an encryption key. The AP and each client PC must be configured to use the same key. Although WEP uses relatively strong 128-bit data encryption, researchers (and crackers) have found a way to crack the WEP encryption. As a result, the WiFi organization introduced a newer, stronger form of encryption called WiFi Protected Access, or WPA—which is in turn based on the IEEE 802.1X authentication protocol.

WPA Encryption

WPA is similar to WEP, but WPA combines encryption with user authentication. WPA was just becoming available as this book went to press, but it should be a standard feature in most home access points beginning in early 2004. Instead of using a shared encryption key, WPA first requires users to identify themselves with a user name and password. If the user passes the authentication test, the AP sends the user a unique key that is valid for a limited period of time. The data connection between the user's PC and the AP is encrypted using the temporary key.

WEP Encryption

While WEP isn't as secure as WPA, it is still reasonably secure and is much better than no protection at all. Virtually all APs provide WEP encryption, and WEP is very easy to configure. In the following example, I show you how to configure WEP on a typical AP and on a Windows XP client PC.

Keep in mind that once you have enabled WEP on your AP, you will need to configure each client PC on your wireless LAN to use the same WEP encryption key.

To begin, connect to your AP's management screen, and locate the WEP settings screen. In the example shown in Figure 7-16, the WEP information is located on the same screen as the SSID and channel settings. It is not necessary to change the SSID or channel to enable WEP.

To enable WEP, select the Enabled radio button. If your router or AP offers multiple levels of encryption, choose the one with the strongest encryption. In this example, the AP supports 40-, 64-, and 128-bit encryption, and I have selected 128 bit.

Most APs allow you to enter the WEP key as a string of hexadecimal numbers or as a string of readable (ASCII) text. Unless you have a thing for hex numbers, choose the ASCII setting, and enter a string of text to use as the encryption key. Although I've used a readable phrase (mumbo-jumbo) in the example, you should use a random string of numbers and letters for your key. Whatever key you choose, be sure to write it down in a safe place; you'll need to enter the key into each of your client PCs.

After you've enabled WEP on the access point, you need to configure the WEP key on each of your wireless client PCs. The first time you attempt to connect to the wireless LAN after you enable WEP, you'll see a screen like the one in Figure 7-17. Carefully enter the key in each of the two boxes, and click the Connect button. If you change the key on the AP, you will need to reenter the key on each of the client PCs.