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Capturing wifi management frames never sees frames with wlan.fc=0x0803

asked 2026-03-25 10:21:35 +0000

brianwyld gravatar image

updated 2026-03-26 07:18:51 +0000

Hi Capturing wifi traffc on windows PC using a netgear A6210. Putting this in 'monitor' mode with ofdm modulation allows me to get what looks like all traffic on a specific channel (all set using wlanhelper in npcap).

However, I cannot see any frames with the FC field with the toDS/fromDS fields set to values other than 0 specifically data frames with toDS=1, fromDS=1. (ie filter wlan.fc==0x803)

I _know_ that there are such frames on the air because my embedded device that I am developing is sending them (nrf5340/nrf7002 combo). If the device sets fc=0800 (ie toDS/fromDS=0) then wireshark sees the frames. If it sets fc=0803 then no frames... A cisco AP is able to see these frames, as is wireshark on a MAC (sadly neither of these are in my office...)

What am I doing wrong that I can't see these specific frames?

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I would question the A6210.

Jaap gravatar imageJaap ( 2026-03-25 17:13:44 +0000 )edit

Are you looking for frames where wlan.fc.ds is 3?

  static const value_string tofrom_ds[] = {
    {0,                       "Not leaving DS or network is operating in AD-HOC mode (To DS: 0  From DS: 0)"},
    {FLAG_TO_DS,              "Frame is entering DS (To DS: 1  From DS: 0)"},
    {FLAG_FROM_DS,            "Frame is exiting DS (To DS: 0  From DS: 1)"},
    {FLAG_TO_DS|FLAG_FROM_DS, "Frame part of WDS (To DS: 1  From DS: 1)"},
    {0, NULL}
  };
Chuckc gravatar imageChuckc ( 2026-03-25 18:36:18 +0000 )edit

Yes, DS equal to 3 (mistakenly typed DA sorry) : edited question to fix this.

brianwyld gravatar imagebrianwyld ( 2026-03-25 19:50:33 +0000 )edit

Ok - just wanted to verify it wasn't a display filter issue.

Capturing wifi traffc on windows PC

To expand on @Jaap comment, search in the npcap issues for netgear or a6210. Your exact scenario doesn't pop up but they do entertain questions about the driver there.

Another option is to bolt (velcro) a Raspberry Pi to your system and do capture with it, feeding the output back to Wireshark on the PC. Kali seems to bundle support for monitor mode now (https://www.kali.org/blog/raspberry-p...) or you do it adding nexmon to a Raspberry Pi OS (previously called Raspbian) image. Raspberry Pi's USB gadget mode enabled a USB connection to emulate a network interface. This would allow Wireshark on the PC to capture with sshdump on the Pi or feed the output back over ssh and read in via interface stdin (-i -).

Chuckc gravatar imageChuckc ( 2026-03-26 14:22:22 +0000 )edit

Captures attached to 7115: 802.11s Decoding Bug (Mesh Control Field) have packets that match radiotap.channel.flags.ofdm == True and wlan.fc.ds == 3

Chuckc gravatar imageChuckc ( 2026-03-26 14:58:23 +0000 )edit

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answered 2026-04-01 14:17:28 +0000

brianwyld gravatar image

The problem is indeed to do with the Windows driver : although the monitor mode for the A6210 looks like it captures all packets, those with wlan.fc.ds=3 weren't seen.

On a linux box (Ubunto) they are captured just fine (after a bit of faffing about to get the interface in monitor mode).

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Asked: 2026-03-25 10:21:35 +0000

Seen: 124 times

Last updated: Apr 01