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There is a terminal airport utility in MacOS that can be used for wireless diagnostics. Detailed here: http://osxdaily.com/2007/01/18/airport-the-little-known-command-line-wireless-utility/

It can be used, among other things, to put the wireless card of the Mac in monitor mode.

To do this, I first disassociate from the existing AP: sudo airport -z

Then bind to the channel I want to monitor: sudo airport -c3

If you then run sudo airport -I, it will confirm for you that the channel has changed. Channel 3 is shown above as an example. You can now start Wireshark or tcpdump to start capturing packets.

However, on my device, Im not able to bind to channels 12 and 13. That is, the following commands don't work:

sudo airport -c13 sudo airport -c12

In both cases, sudo airport -I does not reflect the change. Wireshark continues to report packets from the channel you were previously monitoring (such as channel 3), rather than the channel you are trying to change to (12 or 13)

Channels 1 through 11 work on the device.

How do I fix this?

Note: About the duplicate tag - although Channels 12-13 are not allowed in the US, I live in India. The router has automatically selected channel 13, and it's working for other devices (Android and iOS). The other question, therefore does not answer mine.

Is there perhaps a configuration change that needs to be performed on the Macbook or is there a fundamental compatibility issue with mid-2014 Macbook Air's which is what I'm using.

Community
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Somy Nona
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  • Where are you located? Channels 12, 13, 14 are illegal in the US. – Tetsujin Nov 12 '19 at 08:43
  • Possible duplicate of [Whats the significance (if any) of wifi channels 12-14?](https://superuser.com/questions/329152/whats-the-significance-if-any-of-wifi-channels-12-14) – Tetsujin Nov 12 '19 at 08:43
  • I live in India, so it should not be a problem. My router is setup accordingly and it has auto-selected channel 13. When trying to monitor the same with my Macbook Air mid-2014, it is not working. It was also purchased in India, so it should - ideally, work. Is there some configuration I have to change so as to use the correct country profile on the Macbook or is it a fundamental compatibility issue? – Somy Nona Nov 12 '19 at 10:55

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Try changing the region on your mac to the region you're in, if you have it set to US it'll refuse to sniff over frequencies that aren't allowed in the US, but change it to India and it should allow you to use channel 13

This should be in settings -> language & region

Edited to clarify: you shouldn't use country settings for countries you aren't in unless you're in a shielded environment

Avery W
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    One really shouldn't choose "another country", but the country one lives in. So in the OP:s instance choosing "JP" is not appropriate. There are reason why wireless channels in a specific area are not allowed, it's not a haphazard decision from the authorities. Even in Japan ch14 is limited to legacy 802.11b only. – Peregrino69 Feb 01 '23 at 14:30