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When you’ve got the Wireless Diagnostics window open, head to the top left of your display towards the menu bar again, click on the ‘Window’ option, and then ‘Scan’.
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Note: you could also type ‘Wireless Diagnostics’ into Spotlight - it’ll bring up the same window for step 2. This will bring up a secret menu with a bunch of other information. Near the top, you’ll see an option called ‘Open Wireless Diagnostics’ - click on that. Once you’re there, push down the Option key ⌥ (next to the CTRL key) on your keyboard and click the icon at the same time. Head up to your Mac’s menu bar and track down the WiFi icon. How To Access the Wi-Fi Scanner in Mac OS X Mavericks How To Access The WiFi Scanner In Mac OS X Yosemite WiFi Signal Strength Explorer is a handy little utility which unlike the normal WiFi icon, shows you the strength of connection via dots/percent in the menu bar and by clicking it, you can access some basic details about your current network.How To Access The Wi-Fi Scanner In Mac OS X El Capitan But it also comes with a downside which is it will also disconnect you and you have to reconnect again. JamWiFi is another free little tool which can not only analyze devices connected to your wireless network, but you can also disconnect them from using your WiFi. While normally you’d need an external WiFi adapter to these kinds of things, most Macs have a network card that supports monitor mode which overall works out pretty well. WireShark is also capable of working in monitor mode, thereby letting you see what other devices are browsing/watching on your network.
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Although it comes with a steep learning curve, it is one of the best packet analyzer apps available. WireShark is an open source and very powerful network analyzer used mainly by network admins and developers.
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