3 min read
When an wireless access point wants to advertise its available networks, it sends out 802.11 beacon frames. These frames are seen by other 802.11 receiving radios, and if you can capture those frames, you can use CloudShark’s Wireless Networks tool to see all of the wireless networks (named with their SSIDs) nearby.
Alternatively, when Wifi stations come online, they may send out a frame called a “Probe Request”. An access point can respond to these requests with a “Probe Response”. These responses contain information similar to those broadcast in a Beacon frame.
When might this be useful? Let’s say you’re the administrator for a public Wifi network in a hotel, airport, or office building. You want to see the networks that a user will see, and that they have the proper security and signal strength for your location. You also want to be on the lookout for rogue access points that might be a danger to your network or reveal a presence that shouldn’t be there.
To do this, you can use a tool like AirTool on a Mac, or you can capture from an access point with built in capture, such as Aerohive or Meraki devices. For our captures below, we used an Aerohive AP managed with their HiveManagerNG cloud service. Once you have your capture in CloudShark, go to “Analysis–>Wireless Networks”. With the magic of web-based capture analysis, we can show you a real live capture and the wireless networks tool:
Wait, is that an iframe of a CloudShark capture up there?
Indeed! Remember that sharing with CloudShark is easy; by setting the capture to public we can collaborate on any of CloudShark’s views. To get a direct link to the wireless networks tool view, we used this link:
In our own network here at CloudShark, we have a lot of active networks, since our sister product CDRouter is busy testing all sorts of broadband routers and wireless APs with their networks on. From the tool, you can see a number of important details:
Here’s a not so tough one: can you find the network that probably shouldn’t be there?
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