eye p.a.

CTS 102: Capturing Wireless Frames

François and Rowell discuss their experiences capturing wireless frames for analysis and what tools they used to do it.

This episode is sponsored by Metageek

Sponsored by Metageek

Capturing Wireless Frames

It’s one of my favorite things to do. Capture wireless frames anywhere there’s a wireless network present. I know. I’m a boring guy. But I can’t help taking a look. In this episode on capturing wireless frames, we go over our favorite tools and apps which help us solve real world problems.

Why should you capture frames? If you want to learn how wireless works, then you need to start diving into frames. That’s how you’ll learn exactly what you need to know by seeing how it works. It’s perfect for learning any of the CWNP certifications and especially for the CWAP. By looking at wireless frames, you’ll begin seeing how wireless devices and access points talk to each other and acquire the shared medium.

A beacon frame displayed from Wireshark.

A sample beacon frame from Wireshark

Another reason for capturing wireless frames is to perform analysis. There may be an issue that’s hard to solve and requires wireless frame analysis. This could be as simple as finding out a device does not negotiate the same parameters as the BSS. Or maybe you’re trying to find out what could be slowing down wireless for every other device.

It’s the old saying, packets never lie. But in this case, frames never lie!

Screenshot from Metageek Eye P.A.

An example of using Metageek Eye P.A.

You can capture wireless frames on any platform such as MacOS, Windows, and Linux. When it comes to the platform of choice, we prefer to use MacOS. By default, you can place the MacOS wireless adapter in promiscuous mode. This mode is used to capture all frames, even those not destined to the host. By utilizing an app such as Airtool, it’s possible to fine tune a frame capture down to parameters such as the channel, channel width, payload or no payload, etc.

Then with Wireshark, the analysis can be performed.

Mojo Packets Analysis

A section of Mojo Packets analysis.

In the episode, François and I speak about our experiences in using frame analysis. I bring up a situation where Skype calls kept dropping but the issue was really a consumer level device trying to take up most of the airtime. There are other examples also described in the episode.

Here are some screenshots of different applications of frame capture and analysis.

Links and Resources

CTS 081: Wi-Fi Apps for Windows

We couldn’t do our work without the valuable apps used in the Windows operating system. That’s what we’ll discuss in this episode. Wi-Fi apps for Windows.

This episode is brought to you by

Sponsored by Metageek

Here are the Wi-Fi apps for Windows that Rowell and I use regularly when we are working at client sites or for any other Wi-Fi project. We certainly have our favorite apps and there are some we use on special cases but take a look at the list below and let us know what you think in the comments.

Metageek Chanalyzer

  • Spectrum Analysis software (For more, listen to CTS066, CTS039, CTS073)
    • Required a piece of hardware to feed spectrum information to the software
      • Wi-Fi Spy dBx
      • Cisco CleanAir AP (much better resolution)
  • Simple and user friendly interface
    • Different views
      • Waterfall view
      • Current spectrum view
  • Ability to record spectrum analysis
  • Can scan both 2.4GHz and 5GHz bands at the same time (if proper adapter is used)
  • Built-in Wi-Fi network scanner
  • Present channel utilization
  • Link to Chanalyzer

Screenshot from Metageek Chanalyzer

Metageek Eye P.A.

  • A different way to analyze a Wi-Fi network
    • Very visual
  • Ability to capture packets (if proper Wi-Fi adapter is used – Airpcap Nx) and display different valuable statistics
    • How much the airtime is used? By who? You will see how much your neighbours affect you!
    • Compare size of packets with amount of data transfered. Helps to visualize that Wi-Fi generate tons of management traffic
  • Ability to import packet capture taken from other programs (Wireshark, AirTool, CommView…)
  • Ability to see the packets
    • With filter capabilities
  • Great to visualize issue and present to customers
  • Geat to gather statistics on how a Wi-Fi network is performing
  • Side note: Great tool to use to learn more about Wi-Fi
  • Link to Metageek Eye P.A.

Screenshot from Metageek Eye P.A.

Ekahau Site Survey

  • Swiss Army knife of Wi-Fi (for more listen to CTS069, CTS009)
    • Site Survey tool (Design, validation, troubleshooting)
    • Wi-Fi scanner
    • Spectrum Analyzer
    • Complete solution meeting the needs of Wi-Fi Engineers
    • Updated on a regular basis
    • Take advantage of the Wi-Fi community to improve the tool (#ESSRequest)
    • Reference in terms of Wi-Fi design and site survey tool today
  • Looks way way way better than AirMagnet
  • Complete set of features
    • 3D Wi-Fi design
    • Reporting and Reporting customization
    • Spectrum Analyzer
    • macOS version (beta)
  • Link to Ekahau Site Survey

Viewing channel overlap in Ekahau Site Survey

Metageek InSSIDer Office

  • Wireless network scanner
  • See what channels are used by other networks
  • RSSI
  • Data rates
  • Protocol
  • Plug in WiSpy dBx for Chanalyzer lite
  • Link To Metageek InSSIDer Office

Screenshot of Metageek InSSIDer

Savvius Omnipeek

  • Heavy Duty Network Analyzer
    • Use to troubleshoot Wi-Fi networks
  • Capture packets and provide insight on the quality of the network (more than just Wi-Fi)
  • Ability to drill down into the packets
  • Ability to use multiple adapters to captures on multiple channels to analyzer things like roaming behaviours
  • Can be overwhelming at first but very powerful
  • Link to website
  • Video from WLPC2016

Screenshot of Omnipeek

Netsh Tool

Screenshot of Netsh

Some other programs worth talking about

What apps are you using in Windows? Did we miss any?