In a recent blog, we showed you how you could do Wi-Fi packet captures on multiple channels simultaneously using Airtool 2 and remote sensors such as the WLAN Pi or a Raspberry Pi 4. But what if you don’t have a remote sensor? 

If you don’t have a remote sensor, you can still do packet captures on one or more channels using external USB Wi-Fi adapters. However, because we can’t use external adapters natively as we do with the Mac’s built-in Wi-Fi adapter, we need the External Adapter Support Environment, EASE. 

EASE is a custom, lightweight Debian virtual machine that allows WiFi Explorer Pro and Airtool 2 to use external USB Wi-Fi adapters on your Mac. When you attach an external adapter to the EASE virtual machine, EASE automatically exposes it to WiFi Explorer Pro and Airtool 2. The base EASE image includes the necessary wireless drivers to support Wi-Fi scanning and capturing. And as long as you use a compatible USB Wi-Fi adapter, you don’t need any additional configuration.

EASE is only available in Macs with an Intel processor. Although virtualization for some ARM-based Linux systems is possible in Apple silicon Macs, tools such as VirtualBox, which we use to manage EASE, are not supported in Apple silicon Macs.

You can imagine EASE as having a WLAN Pi or Raspberry Pi running on your local system. Using a USB hub, for example, you can attach multiple compatible Wi-Fi adapters to EASE and use them for Wi-Fi scanning and capturing using WiFi Explorer Pro and Airtool 2.

To learn how to install and use EASE with WiFi Explorer Pro, please read Using external USB Wi-Fi adapters with WiFi Explorer Pro.

Installing EASE

Using EASE with Airtool 2 is very easy, just download and install EASE following the instructions here. Once installed, follow the steps to attach one or more multiple adapters to the EASE virtual machine.

To use EASE with Airtool 2, we recommend Airtool 2.1.1 or higher.

After connecting the first adapter, Airtool 2 will automatically add EASE as a remote sensor and make it available as a capture option.

Using EASE

For capturing on a single channel, choose “EASE” from the Airtool menu and then specify the interface name (e.g., wlan0), channel, and channel width. The first adapter that you connect to EASE will be named wlan0, the second adapter wan1, the third adapter wlan2, and so on. 

If you want to do a capture on multiple channels:

  1. Connect one external adapter per channel and choose “Multi-Source Capture” from the Airtool menu.
  2. Add the same number of entries and select EASE as the sensor in all of them.
  3. For each entry, specify the interface name and choose the channel and channel width.
  4. Start the capture.

VirtualBox has a limit in the number of USB adapters the virtual machine can recognize. You can connect up to 8 USB adapters to the EASE VM.

When you click “Start Capture,” Airtool 2 will connect to EASE, set each interface in monitor mode, configure the channel and channel width, and start a packet capture on all interfaces simultaneously. As Airtool 2 receives packets from each wireless interface, it will merge them on the fly based on their timestamp to generate a single capture file.

You can learn more about capturing on multiple channels here.

Conclusion

In Airtool 2, you can do captures on one or more channels simultaneously using remote sensors and multiple compatible Wi-Fi adapters. If you don’t have a remote sensor but have an Intel Mac, you can still use external adapters to do packet captures using EASE. EASE is a custom, lightweight virtual machine that allows Airtool 2 to use external USB Wi-Fi adapters for packet capturing.