Wi-Fi Scanner Tool is Native in Mac OS X, Here’s How to Use it

Jul 31, 2012 - 20 Comments

The native and already powerful Wi-Fi Diagnostics Tool in Mac OS X got a redesign in Mountain Lion and Mavericks and with it came some new features that make it better than ever. One of the best new additions is the built-in Wi-Fi scanner tool, which is a full-featured wifi stumbler to find and discover nearby Wi-Fi networks – even those that don’t broadcast their network names.

Wi-Fi Scanner in Mac OS X Mountain Lion

This is really an advanced feature that has a wide variety of potential uses beyond just locating access points, most users would be best off just using the Wi-Fi menu to find available wireless networks to join. For those that want a wireless stumbler, here’s how to find and use it.

First you’ll want to make the Wi-Fi Diagnostics app readily available by bringing it to LaunchPad or the Dock, to do that:

  1. From any Finder window, hit Command+Shift+G and enter the path: /System/Library/CoreServices/
  2. Locate “Wi-Fi Diagnostics” (or “Wireless Diagnostics”, depending on OS X version) and drag and drop it into Launchpad or the OS X Dock for easy access

Now that you have the Wifi app in an easy to find location, using it is slightly different depending on your OS X version. Newer builds of Mountain Lion (10.8) changed it slightly, and those changes are reflected in OS X Mavericks (10.9) as well. Outside of accessing the tool, all functionality remains the same.

If the app is called “Wi-Fi Diagnostics”, here is what you need to do:

  1. Launch Wi-Fi Diagnostics and ignore the frontmost menu, instead hit Command+N to summon the new “Network Utilities” window (this is also where the wireless signal strength measurement tool is located now)
  2. Click the “Wi-Fi Scan” tab to get started with the wireless stumbler tool

If the app is called “Wireless Diagnostics”, to access the scanning utility is slightly different:

  1. Open Wireless Diagnostics and ignore the menu, instead pull down the “Window” menu and select “Utilities”
  2. Select “Wi-Fi Scan” tab to summon the scanner and stumbler wireless networking tool

Under the Wi-Fi Scan tool, you will see all available network names and their respective BSSID, channel, band, protocol (wireless n, g, b, etc), security type, their signal strength, and the noise level of the signal.

The tool defaults to scanning once and displaying the found information, but you can turn on Active Scan or Passive Scan mode to constantly search for new networks by clicking on the “Scan” pulldown menu in the lower right corner.

There are plenty of potential uses for this utility and the wireless stumbler, whether it’s optimizing networks, reducing interference and noise, or discovering those around you, but the wifi diagnostics app also includes many powerful features that allow you to capture network traffic, be it data that is sent from the computer in use or even all nearby wireless networks. Ultimately those latter functions and their uses are far beyond the scope of this article, but previously Mac users had to use third party apps like Kismet or boot from a separate Linux installation to access advanced network capturing abilities.

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Posted by: William Pearson in Mac OS X, Security, Tips & Tricks

20 Comments

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  1. parakeet says:

    VERY interesting that you can find hidden networks and capture network traffic with this.

    I also find it interesting that Apple is hiding all the powerful tools in the CoreServices folder rather than Utilities these days, anything to make of that or just Apple hiding clutter from novices?

  2. Scott says:

    Easier way…
    While holding OPTION, click the Wi-Fi icon in the menu bar and select “Open Wi-Fi Diagnostics…” from the bottom of the drop-down menu :)

  3. preller says:

    I guess the WiFi menubar applet uses the same framework to find networks as the Network Utilities app.
    Shouldn’t it be possible to hack that applet, so that it displays the hidden networks?

  4. Nemrod says:

    No App available on my OS X

  5. Navid says:

    Mine was Command + T to bring up Network Tools View…Nice tip Scott

  6. Krista says:

    Thanks, this is awesome !

    Reminds me of Kismac

  7. iDeMi says:

    Very nice utility. I previously used iStumbler for this. What I have noticed is that iStumbler is displaying the names of the closed/hidden WiFi networks and the ML WiFi utility is not.

  8. aidan says:

    well i followed the instruction opened wi-fi diagnostics when i use command+N i get notes and when i use command+T i get fonts lol i guess this new retina display mac book pro is coded differently

  9. Mike says:

    Follow Scott’s instruction: While holding OPTION, click the Wi-Fi icon in the menu bar and select “Open Wi-Fi Diagnostics”, then press COMMAND+N to get to the Network Utilities.

  10. Lucky says:

    I played with this utility and I got my Wi-Fi card stuck in monitoring mode. How can I turn this off?

  11. scidude says:

    @Mike and @aidan
    I’ve known about the option “secret” menu items for some time now. There has never been a “Open Wi-Fi Diagnostics” item there, as aidan says. And also same as aidan, when I hit command + N, some notes thing comes up, and command + t brings up fonts.
    I have Lion, not Mountain Lion, everything up to date, and a mid 2009 macbook pro 17 inch, so it’s strange that his retina mbp is doing the same thing.

  12. McVin says:

    Hi, I’m a mac newbie and I got a question to ask.

    I’m staying in a house full of students that share 1 internet line. Can the new wifi-diagnostic tool in Mountain Lion OS helps me to monitor the traffic flow? As in to detect is there any P2P activities going on so that we are able to find out which inconsiderate bas**** is making the line lag.

    And how do I view the “Captured Traffic” report? Please reply, thank you. :)

  13. Nilesh Parmar says:

    Another tip bites the dust – great tip man and i didnt need to download any tools :)

  14. richard says:

    doesn’t really tell you how to use it like the title suggests, just how to find it…

  15. Winski says:

    OR, you can go get a REAL STUMBLER for your WiFi environment at http://istumbler.net…….

    MUCH better Data.. MUCH better tracking… MUCH better granularization… MUCH better app – PERIOD.

    I prefer the rev. 99 versus rev. 100.. It has an added category in the left hand column called ‘Spectrum’… It breaks down WHERE the signals are with respect the channels and frequencies versus the ones allocated by the various international licensing bodies for global WiFi propagation… Handy…

  16. Linus says:

    In Mavericks the app locations is:

    /System/Library/CoreServices/Applications

  17. Jesse says:

    Just like lucky said. I Also got my wireless adapter stuck in monitoring mode and have no fucking clue how to get it back to normal… Someone please help me!?!?! I have business to handle and I can’t send the files from my phone!!!!

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