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Go Wireless
Pages: 1, 2, 3

Connect to a Public Wireless Network

The point of wireless networking is not necessarily to do away with a few feet of cables, but to make a network do things it could never do before. For instance, if you have a portable computer equipped with wireless, you should be able to walk into any airport, coffee shop, hotel, or college dormitory and connect to the Internet in a matter of seconds. In more populated areas, it's not uncommon to walk down the street and have your pick of WiFi networks. (See the sidebar for an extra consideration.)

The Ethics of WiFi

Once you get the technical details out of the way, the one remaining hurdle when considering using someone else's Internet connection is a question of ethics. There are countless personal wireless networks around the globe, and most of them, you'll find, are unsecured. This means that you can literally walk down the street in a populated area and probably find a working wireless Internet connection before you reach the end of the block. Some will have been left open intentionally, but most will be unsecured merely because their owners don't have the benefit of the Section 7.5.1 procedure detailed earlier in this chapter.

Now, just because you can connect to these networks, does it mean you should? Are you taking advantage of someone else's ignorance by breaking into their private network, or are you simply making use of a public resource that you'd be equally eager to share?

I'm not about to try to solve this dilemma in these few pages; I only wish to raise the question, and to suggest that if you do ever decide to utilize someone else's wireless network, do not do any harm. Think about your impact, both on the bandwidth of the foreign network and the privacy of those who operate it. And then tread lightly.

As described in Section 7.5.2 earlier in this chapter, you can connect to any unsecured wireless network that Windows XP's built-in WiFi sniffer is able to detect. (The exceptions, of course, are those networks requiring a paid subscription or account access, but that's a different story.) This applies to networks you encounter while you're on the road, as well as those that are in range of your home or office.

Router Placement 101

The tiny WiFi transceiver in your laptop should be capable of picking up any wireless network within about 100 feet. If indoors, this typically includes no more than about 2 or 3 walls, and perhaps one floor or ceiling. But the placement of your wireless router and the arrangement of natural obstacles near it will have a significant effect on the strength and range of your WiFi signal.

Assuming you're using a setup like the one pictured in Figure 7-6, your router will need to be within spitting distance of your DSL or cable modem. But provided that the cable from your modem to your router is long enough, you should have a little leeway here.

Your router should be out in the open; don't put it under your desk, in a drawer, or behind a metal file cabinet. If you're feeding more than one computer, it should be placed in a central location, if possible. Use the signal strength indicator (Figure 7-10) to test various configurations. Consider cabling stationary computers so that you can optimize the placement of the router for your portable ones.

Both the 802.11b and 802.11g standards operate over the 2.4Ghz band, which is also inhabited by cordless phones and microwave ovens. (The black sheep of the family, 802.11a solves this problem by using the 5Ghz band, but its short range and limited compatibility make it an unpopular choice.) This means that you'll get better results if you move the router away from any cordless phone base stations, televisions, radios, or TV dinners.

If, after adjusting the placement of your router, you still need more range that it seems to be able to provide, consider either a repeater (range extender) or an aftermarket antenna.

The problem is that by connecting to these networks, you're exposing your computer to the full array of viruses, hackers, and other dangers present on any network. [3] The solution is to take action to protect your computer (or workgroup), and the necessary steps depend on the scenario.

Scenario 1: Single-Serving Internet

Say you've just sat yourself down at a sidewalk cafe, and pulled out your laptop. (This scenario also applies to hotel rooms, airports, and coffee shops.) You boot up Windows, open the "Choose a wireless network" window as described in Section 7.5.2, find a local network, and connect for approximately 20 minutes to check your email. When you're done, you'll likely never use this network again.

Now, if you typically use your laptop from behind a wireless router at home (as described in Section 7.5.1 earlier in this chapter), you'll want to take some extra steps to secure your computer before you connect elsewhere. Since you won't have your router with you on the road, and thus won't have any dedicated firewall hardware, you'll want to employ the built-in Windows Firewall software (or a third-party firewall solution), as described in Section 7.6.2 later in this chapter. This will provide minimal protection, insufficient for the long haul.

Scenario 2: The Long Haul

Say you just moved into an apartment complex (or have a small business in an office building) that provides free wireless Internet. Naturally, you would never want to connect your computer or workgroup to this wireless free-for-all without some sort of reliable, long-term firewall solution. Now, since this is not your own private Internet connection, you can't just plug in a router to facilitate your firewall. But you can add another device, a wireless bridge, in order to build an "island" of sorts, in a sea otherwise filled with danger.

Figure 7-24 shows a sample setup involving a wireless bridge and a router. The two dotted rectangles represent the scope of the two different WiFi networks in effect: your own private, encrypted wireless network is shown on the right, and the public network is illustrated on the left. (Your bridge and router actually form a tiny, third network, complete with its own set of IP addresses separate from those in either of the two wireless networks.)

Figure 7-24
Figure 7-24. Use a wireless bridge in conjunction with a wireless router to protect your workgroup when connecting to a public Internet connection

WARNING This can be tricky to set up, and may require some trial and error to get it right. Depending on your specific hardware and your needs, you may need to adjust this procedure somewhat. For the simplest setup, make sure your bridge and router are manufactured by the same company.

Here's how you set it up:

  1. Obtain a wireless bridge, and follow the procedure laid out in its documentation to set it up with the aforementioned public wireless network. (This typically involves plugging it directly into your PC or one of the numbered ports of your router.) While you're here, obtain the IP address of your bridge; it'll be something like or

  2. When you're done setting up the bridge, connect it directly to the WAN port of your wireless router. (This is the port into which you'd normally plug a DSL or cable modem.)

  3. Configure your wireless router so that it has a Connection Type of Static IP. (Refer to your router's documentation for the specific details on this and the next few settings.)

  4. In the router setup, set the Gateway address to the IP address of your bridge that you obtained in step 2.

  5. Then, set the IP address of the Internet connection (as the router sees it) to a fictitious IP address in the same subnet as your bridge. This means that the first three numbers of both IP addresses should be the same, but the fourth should be different. That is, if your router is located at, then you could set the IP address of your Internet connection to something like or

  6. Finally, set the DNS server addresses in your router setup to the IP addresses of your Internet Service Provider's DNS servers.

    TIP: If you don't know what Internet Service Provider you're using, connect your PC directly to the wireless network in question. Open a web browser, type in the address bar, and press Enter; this will show the IP address of your Internet connection. Then, open a Command Prompt window (see Chapter 10) and type nslookupip_address, where ip_address is the set of four numbers reported by This should give you the name of your ISP, plus some extra stuff. So, you might see something like, which means your ISP is "" Then, it's only a matter of visiting their web site and determining their DNS server addresses from their online documentation!

This should do it. The bridge funnels the public Internet connection into your router, and your router funnels it to the computers in your workgroup. The router acts like a firewall, provided that you connect all your computers directly to your personal WiFi network, and not the public, unsecured one.

Among other things, your bridge/router combination will serve as a repeater (aka range extender), and should boost the signal strength and might even improve performance over connecting directly.

Add Wireless Support to Any Device

As soon as you have your wireless network up and running, you'll probably be inclined to do away with as many cables as you can. This feeling is normal; there's no need to seek psychiatric help or psychic guidance.

There are ways to add support for wireless networking to nearly any computer or device, further illustrating what you can do with a wireless network:

Desktop computer

Add a wireless PCI card just as you would an Ethernet NIC (network interface card). When shopping for a WiFi NIC, look for a card with an adjustable, external antenna (versus merely a nub.) Another alternative is a USB-based WiFi adapter, which will be easier to install, but probably at the expense of some performance.

Laptop computer

One of the biggest hassles of using a Digital Video Recorder (DVR) is that you need to connect it to a phone line so that it can download the latest program data. If you have a newer DVR (such as Series-2 TiVo) that comes with built-in networking support, you can use a USB-based WiFi adapter and finally cut the cord. If you have an older Series-1 TiVo, you'll need to add a TurboNet card (available at and then connect that to an external WiFi bridge. Alternatively, you can use a AirNet card (also available at along with a PCMCIA 802.11b adapter you provide, but its range will be more limited than the aforementioned bridge. See TiVo Hacks (O'Reilly) for more ways to modify your TiVo.

Video Game Console

Own a Playstation2, XBox, or other network-capable video game console? Just plug a wireless bridge (sometimes called a wireless game adapter) into your console's Ethernet port, and play head-to-head games without the network cables stretched across your living room.

Handheld PDA

As introduced in the beginning of this chapter, there are two prevailing wireless technologies: WiFi and Bluetooth. While some handhelds come with built-in WiFi, a larger percentage support Bluetooth (and only a select few play for both teams). Although only WiFi-equipped handhelds can connect to the WiFi networks discussed throughout this chapter, you'll need Bluetooth support if you want to connect to the Internet with your Bluetooth-equipped cell phone. (The same goes for laptops; get an inexpensive Bluetooth USB dongle to connect your Windows PC to your cell phone wirelessly and surf the web from the park or even the train!)

Now, some higher-end PDAs come with WiFi or Bluetooth support built in, while others have special expansion cards that provide connectivity. You can get a WiFi SecureDigital (SD) card or a Bluetooth SD card that will fit in many PalmOS and PocketPC handhelds, but if you only have one SD slot, you'll have to remove your memory card. If you need the wireless support, you may prefer to replace your PDA with one that has WiFi or Bluetooth (or both) built in, and do away with the awkward protrusion of the expansion card.

Digital camera

Some high-end digital cameras now have WiFi options, allowing you to send your photos to the hard disk of a nearby computer wirelessly, either in batches or immediately after you take them. Unfortunately, this only works in the studio (as opposed to outdoors), where you'd be in range of your wireless router. At the time of this writing, there are no wireless cards you can conveniently insert in place of your digital film, but it shouldn't be long.

Video camera (webcam)
Home stereo

Several companies sell WiFi music players that connect your MP3 collection on your computer to your component stereo system and allow you to hear your music on something better than the tinny computer speakers you're likely using now.

Car stereo

At the time of this writing, a WiFi-enabled MP3 player in your car is only vaporware, but keep your eyes open. Soon, manufacturers promise us, you'll be able to send digital music to your car wirelessly. I can't wait for my car stereo to catch an airborne virus.

There's virtually no limit to the number of devices you can make wireless, provided that they support some form of networking already. If all else fails, a wireless bridge, as illustrated in Section 7.5.3, earlier in this chapter, should allow you to connect just about anything to your wireless network.

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