Gearing Up for War Driving
It’s pretty simple to get started war driving. This chapter will show you how to gather the components needed for a war drive.We will install the system into a car, go on a drive and record what we find. You may be surprised at what’s out there!
You will need the following items:
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Overview of the War Drive
Imagine yourself driving late at night. You have a full tank of gas, it’s dark, and a faint electronic glow illuminates the right side of your face. As each house or building passes by, your laptop blips out another group of unusual words like tsunami, default, dog house, taffy, 101, spock, or who knows?
Or picture yourself driving home from work, taking the scenic route— through the commercial district. Just to see what pops up.
Perhaps on a road trip, you are passing trucks as if they are standing still. As you approach a weigh station, a blip pops up on your laptop. Hmm... a new access point. This one reveals the presence of a Wi-Fi weigh station network.
You’ve started to experience the allure of war driving. Invisible waves pop up on your computer screen revealing the unknown and unseen. The act of driving a car equipped with a computer, a wireless card, and software designed to scan for wireless networks has come to be known as war driving. The term war driving derives from an idea from the early 1980s to dial many telephone numbers to find a computer modem: war dialing. The term itself was coined from the dialing program made popular in the 1983 movie WarGames.
One of the interesting aspects of war driving is that you will find wireless access points where you least expect it. From a deserted highway in the middle of nowhere to a rural truck stop to a bustling cityscape, wireless networks are exploding onto the airwaves. The phenomenon is quite remarkable.
Here are some places to visit to get you started:
Figure 5-1 shows the view during a rare daytime war drive.
The original term war driving has also spawned a host of derivatives applying to many situations in which people scan while not actually driving—for example, war walking, war strolling, war boating, and war flying. They all mean one thing: looking for wireless networks, usually while moving.We prefer to scan while driving.
Some people have promoted the idea that the
War driving software has no problem scanning at freeway speeds, although range is limited. And you can start the laptop and leave it alone during normal commutes or take side trips on the way home just because you haven’t scanned that area before. Regular war drivers frequently go out of their way to grab the signals along a stretch of road they haven’t war driven before. If you become enamored with the results of your war driving, it becomes a numbers game where you seek the highest number of access points found.
Keep in mind that the software does most of the work during war driving. You just need to keep the laptop running. Figure 5-2 shows how all this comes together
It All Starts with the Wireless Adapter
The essence of war driving is to use the innate capacity of a wireless network adapter to scan for networks, just as it was designed to do. The IEEE specification for 802.11b (and other 802.11 specs) specifically requires that an adapter be able to detect wireless networks in the area. The design calls for a user to bring up some sort of network selector and be able to choose the network as displayed by the SSID.War driving software in general exploits this scanning ability, with the special distinction that it records and saves the networks for later review.
Recall from setting up your wireless access point in Chapter 4 that an SSID is the identification broadcast by a wireless access point. War drivers will record the SSID along with a host of other information sent out by the access point.
You need to plug in the adapter somewhere, so it really starts with a computer. Since computers come in every form, it is important to determine the interconnections available.
Types of Adapters
The explosion of Wi-Fi products on the market has created every form imaginable for wireless network adapters. Recent mass-market developments have begun the transition from external, after-market devices like PCMCIA cards and USB adapters to integrated wireless devices, such as laptops using Intel Centrino mobile technology and PDAs with built-in Wi-Fi adapters. See Table 5-1 for a general overview of the types of adapters available.
You will have the best luck getting software to work with an after-market adapter. Most integrated devices do not have the open-development community backing the drivers and integration needed for the most popular war driving software. But don’t give up. Everything is worth a try!
When choosing an adapter, look for a few key items:
Some wireless cards outshine others in the war driving arena. A few PC cards are very popular with seasoned war drivers. Many of the cheapest wireless cards are not used much due to their poor performance. Results from those cheaper cards will be mixed. But if you have something laying around, go ahead and give it a try.
The Orinoco PC card in Figure 5-1 (
The first few versions of NetStumbler only supported cards like the 802.11b Orinoco, which then used an internal chip set called Hermes. Old school war drivers reminisce about using Windows 98, NetStumbler version 0.20, and an Orinoco card. All the tools needed for a fun evening spent cruising around town.
A fairly recent addition to the marketplace is the Senao PC card (www.senao.com). This 200 mW card produces a lot of power for a PC card. (Most cards only transmit about 30 mW!) And it may also have a more sensitive receiver. The Senao card comes in several variations. This card is a great war driving card, but is not very well supported by the manufacturer or by the war driving community. If you have problems getting it working with your system, a Google search may end up being your best hope.
External Antenna Connectors
Wireless network adapters are designed by the manufacturer to connect to a wireless LAN. There are some exceptions to this, but in general, they are not designed for war driving and don’t have the external antenna connector, you will need to add an antenna. The antenna built in to the adapter is made to connect to a strong, local signal.When war driving, you want to pick up the weakest signal possible to increase your chances of detecting more distant wireless nodes.
The diversity antennas on a PC card are designed to be small enough to fit on the card. And they work just well enough for a local wireless network. Figure 5-3 shows the internal antennas on the popular Orinoco PC card used for war driving. Notice the small footprint of the card’s internal antennas (the two L-shaped metal plates). Attaching a high-gain external antenna will add receiver sensitivity and boost the output signal beyond the capability of the card itself.
Also in Figure 5-2, you can see the connector used to add an external antenna. As discussed in Chapters 2 and 3 on building antennas, an external antenna is essential for best results. This is crucial when driving in a car. The large amount of metal around the passenger cabin acts as a giant shield, blocking many wireless signals. A rooftop external antenna will increase results at least twofold.
A Faraday Cage is a shielded enclosure used to test radio and microwave equipment without leaking signals to the outside of the cage. The passenger cabin of cars and trucks acts much like a Faraday Cage in that signals do not transmit well outside of the passenger cabin due to the surrounding steel.
When choosing a wireless adapter, consider the extra benefit you get from an external antenna. As discussed in Chapter 1, you will need to use a pigtail to connect the fat RF cabling, used with an antenna, to the smaller connectors used on Wi-Fi adapters.