Overview

An important part of laptop PC troubleshooting involves wireless connections and security issues.

Understand wireless connections

These days, the vast majority of laptop PCs come equipped with wireless network adapters that let users make network connections without having to connect a cable to their computers. However, taking advantage of this convenience means understanding how to set up and use wireless network connections. Wireless networks have substantial capabilities, so it's necessary to understand how they work.

The examples and techniques in this brief focus on Windows Vista.

Understand wireless network settings and setup

Wireless networks depend on special-purpose radio receivers and transmitters that substitute the exchange of messages over the air for the exchange of messages that occurs over wired connections on conventional networks. When you power on your PC, Windows Vista automatically searches for available wireless networks.

The network icon in the system tray, shown in Figure 1, enables you to view a list of local networks that Windows Vista detects. Notice that the network icon in this figure is marked with a red X, which indicates no network connection is currently established.

Figure 1: A red X indicates no network connection is active.

When you click this icon, a window opens indicating you're not connected to a wireless network, as shown in Figure 2.

Figure 2: The detail window for the network icon provides a link to create a network connection.

The window also includes two hyperlinks: Connect to a network and Network and Sharing Center. Click the Connect to a network link to open the Connect to a network window, shown in Figure 3.

Figure 3: Connect to a network window.

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Information appears in three columns in this list:

• Network name: On the left is a list of wireless networks in the area. Any network that appears as "Unnamed Network" requires you to supply its name as part of establishing a connection.
• Security status: The center column indicates network security status. Security-enabled means the network uses encryption that requires users to have a special key or passphrase to establish a connection. Unsecured means the network is available to all users without any restrictions. This is typical for many hotspots at hotels, coffee shops, and other public locations.
• Signal strength: On the right is a signal strength indicator. Five green bars indicate maximum signal strength and quality, whereas one green bar indicates minimum signal strength and quality. You generally need at least two bars to make effective use of a network connection.

What's in a wireless network name?

To attach to a wireless network, you must be able to communicate with a wireless router or wireless AP (access point) in your immediate vicinity. Most wireless routers and APs operate in a range up to 100 meters or about 328 feet. All wireless networks are identified by a name, also known as an SSID (service set identifier). A wireless router or AP can be configured to broadcast its SSID; in that case, the name shows up in the first column in Figure 3. If SSID broadcasting is turn off, the network name displays as "Unnamed Network".

Many open source programs, such as NetStumbler, work with most wireless network adapters on laptop PCs and can easily discover SSIDs for unsecured wireless networks. Therefore, when you set up a wireless network, always use strong encryption and consider turning off SSID broadcasts as a security measure.

Understanding the Wireless Network Connection (WNC) tool

The tool that's displayed in Figure 3 is called the WNC, and it's what you use to make and break wireless connections on your Windows Vista laptop PC. When you need to manually create a network connection (meaning Windows Vista didn't automatically detect the network), you need the following information:

• Common wireless technology: To communicate with any wireless router or wireless AP in your vicinity, your wireless network adapter must be able to use the same technology the router or AP uses. In general, this means conforming to one or more versions of IEEE 802.11x, such as 802.11a, 802.11b, 802.11g, or 802.11n.

A common synonym for 802.11 is Wi-Fi (wireless fidelity), which is actually short for 802.11b Wireless Fidelity but now commonly stands for all forms of 802.11 wireless networking.

• Network name (SSID): If the SSID is broadcast, it's in plain sight for all to see and use. If it's not broadcast, you must know this case-sensitive name to access any network that shows up as "Unnamed Network" inside the WNC.
• Shared security scheme and key: If a network uses an encryption scheme, you must know which scheme it uses and the associated network key or passphrase. 802.11 networks may use WEP (Wired Equivalent Privacy), WPA (Wi-Fi Protected Access), or WPA2 (version 2) for encryption. WEP is the least secure whereas WPA2 offer the most security.

Always use the strongest security scheme your router or wireless AP and wireless network adapters can share.

More sophisticated networks use a RADIUS (Remote Authentication Dial-In User Server) server to supply keys to users with the proper credentials. Most home, hotspot, and small office networks use PSKs (pre-shared keys) instead. That's why you see options in Windows Vista for WPA-Personal and WPA-Enterprise. Personal means you use a PSK, whereas enterprise means you access a RADIUS server.

• Shared encryption: This is TKIP (Temporal Key Integrity Protocol, formerly known as WEP2) or AES (Advanced Encryption Standard).

Most 802.11 adapters offer Auto as configuration option, as well as TKIP and AES, so the adapter can use whatever the wireless router or AP uses. AES is more secure and thus preferable to TKIP.

Next, learn how to create wireless connections and connect to network.