Using Wireless Diagnostics: macOS Big Sur Through macOS High Sierra
How you use Wireless Diagnostics on your Mac depends on your version of macOS or OS X. Here’s how to use it with macOS Big Sur (11) through macOS High Sierra (10.13):
What the Wi-Fi Diagnostics App Does
The Wi-Fi Diagnostics app is designed primarily to help users resolve Wi-Fi issues. To assist you, the app can perform some or all of the following functions, depending on the version of macOS or OS X you’re using. The Wi-Fi Diagnostics app’s main functions are:
Monitor Performance: Provides a near real-time graph of signal strength and signal noise. Also, generates a log of signal performance over time. Record Events: Can log specific events, such as users connecting to or disconnecting from the Wi-Fi network. Capture Raw Frames: Allows you to capture data sent over the wireless network, data sent or received by your computer over the wireless network, and data from any nearby network to which you have access rights. Turn on Debug Logs: Allows you to capture debug-level events occurring on your wireless network. Scan for Wi-Fi Networks: The scan function looks for all Wi-Fi networks in your general area and shows key information about each one, including strength, noise level, and channels being used. In addition, the Scan function also suggests the best channels for you to use for your own Wi-Fi network, a helpful feature if you’re in a crowded Wi-Fi environment. (OS X Mavericks and later) Info: Provides text-based details about the Wi-Fi network you’re currently connected to, including the transmit rate, security protocol in use, channel, and band.
You can use any one of the functions individually. Not all of the functions can be used concurrently with some versions of the Wi-Fi Diagnostics app. For example, in OS X Lion, you can’t monitor signal strength while capturing raw frames. The most useful function for most Mac users is the one that monitors signal strength and noise. With this near real-time graph, you can discover what’s causing your wireless connection to drop from time to time. You may find that whenever your wireless phone rings, the noise floor jumps up to squash the signal received, or maybe it happens when you’re microwaving pizza for lunch. You may also see that the signal strength is marginal and that moving your wireless router may improve the Wi-Fi connection’s performance. The other useful tool is for recording events. If you’ve been wondering whether anyone is attempting to connect to your wireless network (and perhaps succeeding), the Record Events function can provide the answer. Whenever someone attempts to connect or does connect to your network, the connection will be logged, along with the time and date. If you didn’t make a connection at that time, you might want to find out who did. If you need a bit more detail than Record Events can provide, try the Turn on Debug Logs option, which will log details of every wireless connection made or dropped. If you want to get down to the nitty-gritty of debugging a network, Capture Raw Frames will do just that; it captures all traffic on a wireless network for later analysis.
Using Wi-Fi Diagnostics: macOS Sierra through OS X Mavericks
Here’s how to use WI-Fi Diagnostics with macOS Sierra (10.12) through OS X Mavericks (10.9). If you’re using OS X Mavericks, accessing the Wireless Diagnostics utilities is slightly different than in later versions of the OS. If you open the Window menu of the app, you’ll see Utilities as a menu option. Selecting the Utilities item will open a Utilities window with a group of tabs across the top. The tabs correspond to the various utilities listed in the OS X Yosemite and later versions of the Wireless Diagnostics app’s Window menu. For the rest of the article, when you see a reference to the Window menu and a utility name, you’ll find the corresponding utility in the tabs of the Mavericks version of the Wireless Diagnostics app.
Using Wi-Fi Diagnostics: OS X Mountain Lion and OS X Lion
In OS X Mountain Lion (10.8) and OS X Lion (10.7), you work with Wi-Fi Diagnostics a little differently.
Accessing the Monitor Performance Log
To view the performance log after running the Monitor Performance function:
Monitor PerformanceRecord EventsCapture Raw FramesTurn on Debug Logs
Wireless Diagnostics Utilities: OS X Yosemite and Later
In OS X Yosemite and later, the Wireless Diagnostics utilities are listed as individual items in the app’s Window menu. Depending on your operating system, you will find the following: Info: Provides details of the current Wi-Fi connection, including the IP address, signal strength, noise level, signal quality, the channel being used, channel width, and more. It’s a quick way to see an overview of your current Wi-Fi connection. Logs (called Logging in the Mavericks version): Allows you to enable or disable collecting logs for specific events associated with your Wi-Fi network. This includes:
Wi-Fi: A general log of Wi-Fi events. 802.1X: Logs network authentication events that use the 802.1X protocol. DHCP: Logs devices requesting IP address assignments. DNS: Logs access to DNS (Domain Name System) hosts resident on your network. Open Directory: Keeps track of any directory services requests. Sharing: Logs file-sharing events on your Wi-Fi network.
To collect logs, select the type of logs you wish to gather data on and then click the Collect Logs button. Selected events are logged until you turn the logging feature off by returning to the Wireless Diagnostics Assistant in the Window menu. Scan (called Wi-Fi Scan in Mavericks): Performs a one-time scan of the Wi-Fi environment, displaying any local Wi-Fi networks, the type of security being used, signal strength, noise, the channel used, channel width, and more. The scan also shows which are the best channels for you to use in your area. Performance: Produces a real-time graph showing signal quality, signal strength, and noise. Depending on the version of macOS OS X, the real-time graph may also include the transmission rate. Sniffer (called Frame Capture in Mavericks): Captures Wi-Fi packets to analyze. Monitor (OS X Yosemite and later): This is similar to the Performance utility, except with a smaller display that you can leave running in the corner of your Mac’s monitor. When you’re through with the Wireless Diagnostics utilities, return to the Assistant by selecting Assistant from the Window menu or by closing any utilities windows you may have open.
Monitoring Wi-Fi Connection
If you’re having intermittent problems with your Wi-Fi connection, select the option to Monitor my Wi-Fi Connection, and then click Continue. This causes the Wireless Diagnostics app to watch your Wi-Fi connection. If the connection is lost for any reason, the app notifies you of the failure and offers reasons for why the signal was dropped.
Quitting Wireless Diagnostics
When you’re ready to quit the Wireless Diagnostics app, including stopping any logging you may have started:
Wireless Diagnostics Report
The Wireless Diagnostics report is saved to your desktop or to /var/tmp (depending on your operating system) in a compressed format. Double-click the diagnostic file to decompress the report. The report files are saved in various formats, depending on which function you were using. Most reports are saved in Apple’s plist format, which most XML editors can read. The other format you will see is the pcap format, which most network packet capture applications, such as Wireshark, can use. Additionally, the Console app included with OS X can open many of the diagnostics files. You should be able to double-click the diagnostics files to view them in the Console log viewer or one of the dedicated viewing apps included in OS X. For the most part, the reports that the Wi-Fi Diagnostics app creates aren’t helpful for casual users just trying to get their wireless network up and running. Instead, the various Wireless Diagnostic utility apps may provide a better way for you to run down any Wi-Fi issues you may be having.
