macOS WiFi – How to Put WiFi Card in Monitor Mode

command linemacostcpwifi

When I run tcpdump, I do so after having connected to an access point.
Is there a way to run tcpdump without having connected already?

Use tcpdump -I. -I will put the chosen interface into monitor mode, and doesn't need to be connected to an access point.

The full command would be (if your Wi-Fi interface is en0):

sudo tcpdump -Ii en0

Try this:

On the mac: Right click the wi-fi icon

Click Create network. By default it will use the name you have given your mac as the network name.

On the other host, it should see the new network. Join it.

Set DisconnectOnLogout=NO:

sudo /Sy*/L*/Priv*/Apple8*/V*/C*/R*/airport en1 prefs DisconnectOnLogout=NO

^{Replace en1 with the interface number of your AirPort card, if it's different.}