The native and already powerful Wi-Fi Diagnostics Tool in Mac OS X got a redesign in modern versions of Mac OS X, and with it came some new features that make the utility 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.

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.

Accessing Wireless Diagnostics in Mac OS X

In modern versions of Mac OS X like OS X Yosemite, OS X Mavericks, you can get to Wireless Diagnostics from the Wi-Fi menubar item:

Option+Click on the Wi-Fi menu item in OS X Choose “Open Wireless Diagnostics”

This is somewhat hidden, but still much easier than accessing it in prior releases of OS X where the app was basically hidden.

Scanning for Wi-Fi Networks with the Mac Wireless Diagnostics Tool

Now that you’re in Wireless Diagnostics, here’s how to use the Scanner:

Go to the “Window” menu and choose “Scan” to immediately open the Wi-Fi Stumbler tool built into Mac OS X Within the Scanner tool, click on the Scan button to scan for available networks

This will open the wireless card to detect all possible nearby wifi networks, effectively stumbling onto available wireless routers and discovering details about those networks.

All available wireless network names, SSID, channels, band, network protocol (wireless n, g, b, etc), the network security type, the network signal strength, and the network noise level of the signal discovered will be listed by the scan utility.

This is obviously much easier in modern versions of Mac system software, but don’t worry if you’re not on OS X Yosemite, you can still access and use these tools with the directions below.

Making Wi-Fi Diagnostics Easier to Access in OS X

For other versions of OS X, like OS X Mountain Lion, you’ll want to make the Wi-Fi Diagnostics app readily available by bringing it to LaunchPad or the Dock, to do that:

From any Finder window, hit Command+Shift+G and enter the path: /System/Library/CoreServices/ 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:

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) 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:

Open Wireless Diagnostics and ignore the menu, instead pull down the “Window” menu and select “Utilities” 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.