Sniffing Hidden Networks
But what if you've turned off the SSID broadcast feature, as described in Section 7.5.1 earlier in this chapter? If your network doesn't show up in the list, simply click Set up a wireless network for a home or small office (on the left side of the "Choose a wireless network" window shown in Figure 7-20). This will start the Wireless Network Setup Wizard (which is also accessible through My Network Places).
Click Next and then type your network's SSID in the Network name (SSID) field, as shown in Figure 7-21.
Figure 7-21. You'll need to run the Wireless Network Setup Wizard to connect to your wireless network if you've opted not to broadcast your SSID
If you've enabled WEP encryption, select Manually assign a network key and click Next. On the next page, type (or paste) your WEP key into the Network key field.
As illustrated in Figure 7-19, many routers allow you to set more than one key; unless you have specific reason to do otherwise, just use the first one (Key 1) in Windows XP.
The length of the key you type is shown to the right of the field. If you're using 64-bit encryption, the key will be 10 characters long (or 5 if you're not typing hex codes); if you're using 128-bit encryption, the key will be 26 characters long (or 13 if you're not typing hex codes).
TIP: Unless you enjoy typing incomprehensible hex codes, turn off the Hide characters as I type option. Then, highlight the text in the Network key field, press Ctrl-C to copy it to the clipboard, click in the Confirm network key field, and press Ctrl-V to paste a copy of the key. If you stored your WEP in a text file, as suggested in Section 7.5.1, you can paste it into both boxes here, and avoid the tedious typing altogether.
Click Next. You'll then be given the opportunity to save your settings on a USB flash drive, theoretically making subsequent setups easier; why there's no option to save to a CD writer, floppy drive, or simply a file on your desktop is a mystery. Select Set up a network manually if you don't have a USB flash drive handy, or if you don't need to set up any more computers. Click Finish when you're done.
From now on, your wireless network will show up in the "Choose a wireless network" list whenever it's detected, even if you've chosen not to broadcast your SSID. If it doesn't show up at this point, it means you've either mistyped the SSID here or in the router setup page (an incorrect WEP key won't cause a problem until you try to connect.)
Configuring WiFi Networks
If there's a problem with your newly added network, click Change advanced settings (on the left side of the "Choose a wireless network" window) to open the Properties window for your wireless connection. Choose the Wireless Networks tab, highlight your network in the list, and click Properties (as shown in Figure 7-22).
Figure 7-22. You may have to fiddle with XP's WiFi settings to get it to connect to secure WiFi networks
Here, you'll have a second chance to enter your WEP key, but you won't have the luxury of being able to see the characters as you type them (as in the Wireless Network Setup Wizard). The easiest way to deal with this is to open Notepad, type (or paste) your key there, and then copy (Ctrl-C) and paste (Ctrl-V) it into both the Network key and Confirm network key fields.
While you're here, choose the Connection tab. The Connect when this network is in range option (it's on by default) determines whether or not Windows XP will automatically connect to this network when it's available. In most cases, you'll want to leave this option checked.
TIP: Now, if you're in the enviable position of having access to more than one WiFi network regularly, and wish to have Windows connect automatically to more than one network, you can prioritize them. Just return to the Wireless Networks tab (Figure 7-22), highlight a network, and click Move up or Move down.
Click OK to save your settings when you're done. If all is well, Windows should reattempt the wireless connection automatically. If it doesn't, you'll need to return to the "Choose a wireless network" window (Figure 7-20), highlight the network, and click Connect.
See the next section, Section 7.5.3, for ways to protect your computer when using someone else's Internet connection.
WiFi tends to be temperamental, not to mention annoying and tear-your-hair-out frustrating. Among the things that can make it difficult to connect to a wireless access point, these are the most common:
- Drivers and firmware
If you ever have any trouble with your wireless router, visit the manufacturer's web site and see if there's newer firmware available for it. Likewise, make sure you're using the latest drivers for your WiFi PCI and PC Card adapters.
- WiFi settings
Make sure both your router and your other equipment are communicating on the same channel (channel 6, 2.437 Ghz, is the typical default) and are using the same SSID.
Are you using an 802.11g router? If so, you can probably set it to operate only at 802.11b speeds, only at 802.11g speeds, or both. Note that if you select "G-only," no older 802.11b equipment will be able to connect to it.
- Reception, Interference, and Performance
Other WiFi Sniffers
Since one of the biggest advantages of wireless networking is portability, it should stand to reason that you should be able to connect to your wireless network with something you can hold in the palm of your hand.
To that end, a number of handheld computers now come with WiFi support. Figure 7-23 shows the WiFi sniffer that comes with some Palm OS-powered handheld computers, allowing you to identify and connect to any available WiFi network.
Figure 7-23. The WiFi sniffer on a Palm OS-powered handheld PDA shows the same wireless SSIDs as Windows XP's built-in WiFi sniffer
A handheld sniffer can be a very valuable tool when setting up a wireless network. Among other things, you can test the range of your wireless router with a handheld sniffer more easily than by lugging around a laptop or desktop PC, allowing you to subsequently adjust the placement of your router for optimal range.