Wireless Network Administration: Wardrivers and Warchalkers - dummies

Wireless Network Administration: Wardrivers and Warchalkers

The recent explosion of wireless networking has led to a few new terms, including wardriving and warchalking. Whether wardriving and warchalking actually represent security threats is a question that’s subject to a lot of debate.


Wardriving refers to the practice of driving around town with notebook computers looking for open access to wireless networks just to see what networks are out there. Some wardrivers even make maps and put them on the Internet.

The basic intent of wardriving is to discover open wireless networks that can be accessed from public places. A side benefit is that it can help network administrators discover holes in their network security. If your network shows up on a wardriving map, be grateful for the wardrivers who discovered your vulnerability. And by publishing it, they’ve given you incentive to plug the hole!

The downside of wardriving is that intruders can check the wardriving maps posted on the Internet to find potential targets.

Wardrivers arm themselves with the following equipment:

  • A car

  • A notebook computer with a wireless adapter

  • An external antenna isn’t a must, but it helps

  • Software that can scan for open wireless networks

  • A GPS, or global positioning system, a device that can automatically track where you are

  • Software that correlates the discovery of open networks with location data obtained from the GPS device

  • Free time

For more information about check out the website, wardriving.


Warchalking refers to marking the location of open access points with special chalk symbols on the sidewalk. The chalk symbols indicate that a network is nearby. So if you’re wandering around downtown San Francisco and you spot a warchalk symbol on the curb, you can sit down at the nearest park bench, fire up your notebook computer, and start surfing the Internet.

The illustration below shows the common warchalking symbol for an open (unprotected) wireless network. The SSID of the open network is listed above the symbol. You may also find other information written, such as the bandwidth of the Internet connection available through the access point.


Warchalking websites like to relate that the practice of warchalking dates back to the Great Depression in the United States, when homeless people used chalk or coal to write symbols on sidewalks, fences, or railroad trestles to provide information or warnings to their fellow travelers. For example, some symbols represented food, water, or safe places to camp, while other symbols represented dangerous areas or aggressive police.