Doug Vitale Tech Blog

NetStumbler and inSSIDer wireless scanners

NetStumbler is a program for Windows that scans for and detects wireless local area networks (WLANs). It displays the characteristics of the WLANs that it finds, such as WLAN type (802.11a, 802.11b, or 802.11g), WLAN name (or SSID), encryption algorithm (WEP, WPA, etc.), and channel (the 802.11 WLAN standard divides each of the 2.4GHz/5GHz bands into multiple channels).

NetStumbler was a very popular wireless tool at one time, however it has fallen by the wayside in recent years because it only runs on Windows 2000 or Windows XP and not on Windows Vista or Windows 7. When I tried to run NetStumbler on Windows 7, it displayed a “no wireless adapter found” error message as seen below.

NetStumbler v0.4.0 main user interface

The NetStumbler v0.4.0 main user interface

To view a screen shot of NetStumbler in use you can use Google Images.

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Although NetStumbler’s creator stated in February 2010 that he was working on a new version of NetStumbler that would be compatible with the latest Windows operating systems, this new release had not materialized by the time of this writing.

In the meantime, NetStumbler has been surpassed by a similar wireless tool, InSSIDer by MetaGeek. Like NetStumbler, InSSIDER is free but unlike NetStumbler, it is open source software (Apache 2.0 license) and currently an alpha version of InSSIDER is available for installation on Linux (Linux page offline, cached here).

InSSIDer is available in four editions: inSSIDer Home v3.1.2.1 (free), inSSIDer v4 (commercial), inSSIDer Office (commercial), and inSSIDER for Android (free app).

InSSIDer works just the same as NetStumbler: you simply launch the executable and the program immediately begins scanning for and displaying information on the WLANs it finds.

inSSIDer v2.1 main interface

inSSIDer v2.1 main interface

Details about the WLANs detected are displayed in several columns as explained below.

  • SSID – the service set identifier or name of the WLAN.
  • Channel – the channel that the WLAN is operating on.
  • RSSI – the received signal strength indicator, or measurement of the power (signal strength) present in a received radio signal. The lower, the stronger (for example, my WLAN whose AP is ten feet away is rated -36 while more distant WLANs are -67 to -88).
  • Security – the type of encryption the WLAN uses to secure its transmissions. ‘None’ means no encryption is used leaving that WLAN wide open. Other possibilities are WEP, WPA-TKIP (aka WPA Personal), and RSNA -CCMP which is the same as WPA2-CCMP.
  • MAC Address – the MAC address of the wireless access point (AP).
  • Max Rate – the theoretical maximum data transmission rate for the WLAN. 802.11g can theoretically reach 54 megabits per second (Mbs); 802.11n can surpass even this speed.
  • Vendor – the manufacturer of the wireless AP, such as Linksys, Netgear, D-Link, etc.
  • Network Type – only two choices here: infrastructure or ad hoc. In infrastructure mode, wireless-capable devices communicate through an access point that serves as a bridge to a wired network infrastructure. Ad hoc mode enables direct peer-to-peer transmissions between wireless-capable devices without the intervention of an AP.
  • First Seen – displays the time when inSSIDer first detected the WLAN.
  • Last Seen – displays the time when inSSIDer last saw the WLAN (presumably before it went offline).
  • Latitude and Longitude – used in conjunction with inSSIDer’s GPS functionality (described below).

The functionality of inSSIDer is expanded by the functions of four tabs that appear in the user interface.

  • Welcome – contains links from the MetaGeek website.
  • Time Graph – displays the up’s and down’s of the WLANs’ signal strengths (color-coded for easy viewing).
  • 2.4 GHz Channels – another graph displaying the signal strength (amplitude) of only the 2.4 GHz WLANs that inSSIDer finds.
  • 5 GHz Channels – another graph displaying the signal strength (amplitude) of only the 5 GHz WLANs that inSSIDer finds.

Apparently you can connect a GPS device to your computer’s serial port and use it in conjunction with inSSIDer; I cannot explore this functionality at present, but MetaGeek maintains a list of supported GPS models on its inSSIDer support forum. By default inSSIDer does not perform logging but you can enable this function by choosing GPS -> Start Logging. InSSIDer saves its logs with the .gpx file extension. You can tell InSSIDer what to call its log file and where to save it by selecting GPS -> Change log file name. To convert your .gpx logs to .kml format, select GPS -> Convert GPX to KML (also see here for more on KML).

As you can see, inSSIDer is fairly simple and straightforward to use. In terms of finding and reporting on existing WLANs in your vicinity, it vastly outperforms the native Windows wireless detection feature (shown below). If you have questions about inSSIDer’s functionality or if you encounter difficulty or errors using it, MetaGeek provides an InSSIDer forum where you can ask for assistance.

Windows 7 WLAN view

The Windows 7 WLAN viewing feature...quite inferior to inSSIDer

Another WLAN scanner you might want to try out is Vistumbler. It boasts even more features than inSSIDer.

Vistumbler v10.5

Vistumbler v10.5

Recommended reading

If you found the content of this article helpful and want to expand your knowledge further, please consider buying a relevant book using the links below. Thanks!

CWNA Study Guide on Amazon CWNA Study Guide CWNA Guide to WLANs on Amazon CWNA Guide to WLANs

Hacking Exposed Wireless on Amazon Hacking Exposed Wireless BackTrack 5 Wireless Penetration Testing on Amazon BackTrack 5 Wireless Pen Testing

War Driving and Wireless Penetration Testing on Amazon War Driving Wireless Pen Testing Wireless Reconnaissance in Penetration Testing on Amazon Wireless Reconnaissance

Written by Doug Vitale

November 20, 2011 at 9:49 PM

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