How do I configure promiscuous mode so that I receive packets from all channels

Weigen Qiu
Posts: 6
Joined: Thu Jul 02, 2020 8:40 pm

How do I configure promiscuous mode so that I receive packets from all channels

Postby Weigen Qiu » Thu Jul 02, 2020 8:49 pm

Hi,
following the sample code simple_sniffer, I was able to run the code I modified to receive detected packets. However, it seems all detected packets are from the same channel (in my case channel 11).

are there any configurations/APIs/ that I need to set in order to receive packets from all channels?

Thanks in advance.
Last edited by Weigen Qiu on Thu Jul 16, 2020 1:32 pm, edited 1 time in total.

ESP_Sprite
Posts: 4112
Joined: Thu Nov 26, 2015 4:08 am

Re: How to I configure promiscuous mode so that I receive packets from all channels

Postby ESP_Sprite » Fri Jul 03, 2020 6:49 am

You can't. In the same way as a FM radio can only listen to one channel at the time, a WiFi radio also can only be tuned to one channel. You can theoretically 'fake' it by quickly sweeping over all the channels, but you'll still miss packets on channels you're not listening to.

Weigen Qiu
Posts: 6
Joined: Thu Jul 02, 2020 8:40 pm

Re: How to I configure promiscuous mode so that I receive packets from all channels

Postby Weigen Qiu » Wed Jul 15, 2020 4:49 pm

thanks ESP_Sprite.

So I was playing with the Raspberry Pi, and the Wifi driver has a monitor mode. Once I witch to the monitor mode, I can receive packets from all channels. I was wondering the difference between monitor mode and the promiscuous mode.

ESP_Sprite
Posts: 4112
Joined: Thu Nov 26, 2015 4:08 am

Re: How do I configure promiscuous mode so that I receive packets from all channels

Postby ESP_Sprite » Fri Jul 17, 2020 9:18 am

No, you can't, as the Raspberry Pi WiFi also only has one radio. They likely use the trick I mentioned earlier, where the radio 'sweeps' over all channels.

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