Wifi6 monitor mode - no data packets

[SimonW1]

Hi there,

I use Intel AX200 card in Ubuntu 20 (kernel 5.8.0-50-generic, Intel fw=55.d9, libpcap=1.9.1) in monitor mode to sniff wireless traffic (iperf data, no encryption). When AP is setup in wifi5 I can see RTS/CTS/Data/BA packets. But when I switch AP to wifi6 then I can only see RTS/CTS/BA, no Data packets at all. Can anyone explain why? Does the Intel firmware support wifi6 data packets to be monitored?

(the AP has very limited settings - in particular I can't control beam forming or OFDMA and I don't think they are ON by default)

[andersling]

@SimonW1 hi, I ecounter this isue too,have you found some method to make it work?  Maybe ax210 ax200 just can capture single user mode packets,when the ap is in mu-mimo ofma mode, we have to send the AID to the  iwlwifi iwlmvm . but i don't known how to do it?

any one have some ideas? thanks@!

pls give us some advice, the experts from intel!

@Intel Experts!

[SimonW1]

Hi andersling,

Still not resolved this. Now that you mentioned mu-mimo - I used iperf option "-P 5" which is 5 parallel data processes. Perhaps indeed this creates mu-mimo ofdma mode at AP. Will check with "-P 1" later

[andersling]

Hi，someone said that if you want to capture mu-ofdma dl packets, you have to send some params to the he_sniffer_params to the iwlmvm kernel driver:

echo 0 00:00:00:00:00:00 > /sys/kernel/debug/iwlwifi/*/iwlmvm/he_sniffer_params 

but it's on the jason nano borad system, i can't find it on normal ubuntu such as ubuntu 20.10 with kernel 5.10.

any idea? thanks!

[SOLGIL]

Hi andersling, 

I have also read similar solution:

       $  sudo echo <AID> <AP/BSS AMC>   >   /sys/kernel/debug/iwlwifi/*/iwlmvm/he_sniffer_params

But, it gives me "Permission denied".

Have you got any clue for this error ? 

FYI, my NUC machine has AX210 on Ubuntu 20.04 with kernel 5.15

[Yukino]

@SimonW1  Him SimonW1

Could you please show me you operation (or command) to capture Data packets? I have tried lots of method but failed.

Could you see Beacon packets or other mgmt frame, such as Probe/Auth/Assoc?