Did you know that more Wi-Fi networks are out there than what your computer can normally see? It's true. But depending on the security settings of the wireless network and its overall signal strength, you might not see these alternate options pop up in the standard Windows network settings dialogue. That's where Wi-Fi scanning applications like NetStumbler or inSSIDer come into play. That, and they're the best way you go about cataloging all the hotspots in your neighborhood from the passenger seat of your moving vehicle.
We've opted to use inSSIDer instead of the more popular NetStumbler because the latter is starting to show its age. We have yet to get it to work on a Windows Vista-based laptop and we have even had problems getting it to notice the network card in an older Windows XP-based laptop. Every time we go to scan, we're treated to a sea of nothingness:
The relatively new Wi-Fi scanning application inSSIDer works like a charm. We've been able to get it to work on the super-old and super-new notebooks we've tested it on, and it detects our Wi-Fi cards and internal devices without any problem. When you fire up the program, picking your proper networking device is the first selection you'll want to make. Look to the top of the screen and hit the drop-down menu. You'll likely see a number of choices, representing the different network adapters and interfaces the program has discovered. Pick the one that sounds most like the actual card or internal antenna you're using--in our case, it's Intel's Wireless WiFi Link.
From there, you'll want to hit up the preferences screen. Get ready for a dozy of a choice on this one: You have but one option to configure. If you're just planning on using inSSIDer as a generic Wi-Fi scanner for your home or apartment, then you'll want to set an expiration time for the various networks you find. That way, the final list you create represents the most recent networks you've found from the scan. If you're planning on strapping your laptop to the roof of your car and driving around the neighborhood, then have the program retain all of the networks it finds regardless of current activity.
From there, head back to the program's main screen. Spit on you fingers for good measure and fire a mighty mouse click toward the "Start Scanning" button. The application will start detecting any and all wireless networks in range. Tabular data fills in the top half of the screen and a lovely signal strength indicator graph on the bottom. The higher the line on the graph, the stronger the signal of the wireless hub.
Once you've let the program run for a few minutes, go and analyze the data that you've collected. For starters, you can easily see which wireless networks are the strongest via the graph that's been created for you. If you've been moving your laptop around during the scan, you should have written down some notes and time indications of where said laptop was so you can then correlate these positions to the signal strengths on the chart. The MAC address of the actual wireless device shows up next to the SSID of the network near the upper-left of the screen. This listing can include hidden SSIDs as well, so don't be surprised if you see more devices here than what you're used to seeing via the Windows network settings.
The channel column provides one of the most useful pieces of information in inSSIDer. If you've been noticing poor results from your wireless hub even though you have a strong connection in signal strength, check to see that other wireless networks with similar strengths aren't encroaching on the same channel you're using for your device. If so, make a change! We recommend you stick to channels 1, 6, or 11, as they're the least likely to be affected by radio interference.
You'll also see what security settings are present on the scanned networks--that column appears to the right of the written RSSI fields. Remember that connecting to unauthorized access points--even if they're open networks--could be illegal in your state. Check the law before treading onto other people's open networks. And even if you're in the clear on that end, know that connecting to an unknown wireless point could put your machine up against any number of problems. The hub could be designed to leech all sorts of information from your system, especially if you go about logging in to your favorite web sites with your name and password combination of choice. This is pretty common stuff we're talking about, but it's important enough to bear repeating.
Finally, inSSIDer presents you with the speed of the wireless networks in question as well as an indicator of when the program saw the network for the first and last times. But where do you go from here? If you're feeling mischievous, you can hop onto an open network and run a comprehensive topology scan using Nmap to discover the IP addresses, open ports, and MAC addresses of all connected devices. You can also fire up Airodump to discover the MAC addresses of the base station and connected devices--perfect for spoofing your MAC to gain access to a filtered, open wireless network. And finally, if you want nothing more than the complete obliteration of your neighbor's wireless network security, you'll want to combine an Airodump scan with Aircrack to burst past WEP and WPA encryption methods. This takes a lot longer to do than you might think. It's also very, very bad, and you should only consider using these tools to find out more about the ins and outs of wireless security.