I'm analyzing probe request packets and I'm seeing that some of them has an undefined values in HT Capabilities section. Why? Is it not required in all probe request packets?

  • Perhaps if TKIP is enabled (i.e. HT features are disabled)? Maybe the dissector in your capture tool is failing to analyze the frame correctly? Or you aren't capturing the complete frame? Something else entirely? It would be hard to say why you are seeing this result, but if you share the capture you are looking at, it may help in providing an answer.
    – YLearn
    Apr 2, 2019 at 5:07
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide and accept your own answer.
    – Ron Maupin
    Apr 19, 2019 at 14:41

1 Answer 1


As I see HT Capability section announced only in 802.11n


There are two 802.11n operating modes: Greenfield (HT) and Mixed (Non-HT). Greenfield can only be used where no legacy systems exist. HT systems will not switch between Greenfield and Mixed, they will only use one or the other.

An 802.11n AP using Non-HT mode sends all frames in the old 802.11a/g format so that legacy stations can understand them. That AP must use 20 MHz channels and none of the new HT features.

See more from this link

PS. Yep it's not full answer. I don't find yet any notes about this behaviors in RFC's or IEEE's

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