On Mon, Mar 14, 2022 at 05:16:32PM -0500, rea...@catastrophe.net wrote: > Trying to manually monitor channel 132, I get an error, SIOCS80211CHANNEL. > > # ifconfig iwm0 > iwm0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500 > lladdr 80:19:34:ab:ab:ab > index 5 priority 4 llprio 3 > groups: wlan > media: IEEE802.11 autoselect > status: no network > ieee80211: nwid "" > # ifconfig iwm0 mediaopt monitor > # echo $? > 0 > # ifconfig iwm0 chan 132 > ifconfig: SIOCS80211CHANNEL: Invalid argument
The device should support this channel. This gives a list: ifconfig iwm0 chan However, monitor mode is not very user-friendly. Try to force it into 11n mode, then it should work: ifconfig iwm0 mediaopt monitor mode 11n ifconfig iwm0 chan 132 In the implementation, the mode determines which channels are available, not the other way around. And for some reason your interface goes into a mode that only supports 2 GHz band channels. This should be fixed, when the user says "chan 132" ifconfig or the kernel should figure out that the mode needs to be switched if it is incompatible with the requested channel. It's one of those bugs that nobody ever runs into unless they are debugging things. > # dmesg|grep iwm > iwm0 at pci5 dev 0 function 0 "Intel AC 7260" rev 0xc3, msi > iwm0: hw rev 0x140, fw ver 17.3216344376.0, address 80:19:34:ab:ab:ab > > Even after a clean reboot I can't bring the interface up in monitor mode > and join anything other than channels 1-11. That is expected. You cannot use network in monitor mode at all, only listen to a channel. In order to join a network, you need to disable monitor mode again first: ifconfig iwm0 -mediaopt monitor -mode -chan
