I am a beginner in pen-testing, and I am interested in learning, but I seem to run into a brick wall when trying to do so. I have an AP which broadcasts in 2.4ghz and 5ghz. Pretty standard. I am using an alfa AWUS051NH as my network card for the testing, so I am certain the problem is not with the adapter. My problem is that when I put the card into monitor mode and regularly run airdump-ng to list the AP's and users, I only see 2.4ghz networks, despite the 5ghz capabilities. I am running the latest distro of kali linux, and I have seen the -C flag in my googling, but it constantly returns the error of Done, frequency not supported or something like that. Here is specifically what I enter when I run airodump;

Put card in monitor mode:

sudo airmon-ng start wlan0

start airodump-ng:

airodump-ng wlan0mon

Is there a way to sniff for 5ghz AP's too? All help is appreciated greatly. Happy hacking!

  • If the AP is operating in 802.11ac mode then your card will not be able to see it; the AWUS051NHv2 is an a/b/g/n device. Regardless, the airodump-ng suite doesn't explicitly support 802.11ac yet and is thusfar untested.
    – Polynomial
    Sep 3, 2017 at 17:52
  • @Polynomial Is there an alternative method to achieve my goal of sniffing out these networks? It seems that there are no 5ghz networks at all in my list of networks, but when I normally go to connect outside of monitor mode, it sees all of them. The end goal is really to de-auth some clients on a 5ghz network, so alternative methods from the aircrack-ng suite are fine. The goal is what matters. Sep 29, 2017 at 2:57

1 Answer 1


You need to make sure your capture card is capable of every flavor of signal modulation that the target devices can use. Your AWUS051NH is a a/b/g/n device. If your target AP and client (the devices whose traffic you want to capture) are 802.11a-, 802.11n-, or 802.11ac-capable devices, your a/b/g/n card won't be able to capture their traffic.

Even just looking for, say, "802.11ac" isn't enough, as there are variations of 802.11ac that not all devices support: 2, 3, 4 and more spatial streams; 80MHz, 80+80, and 160MHz-wide channels; MCS 8 and 9 (256-QAM), various channels that are legal/illegal in different countries, that equipment designed for different countries may or may not support, and more.

You must also make sure your capture device is positioned "in between" the target AP and the target client. That is, where it can receive transmissions from the target AP at least as well as the target client can, and where it can receive transmissions from the target client at least as well as the target AP can.

You also need to make sure your interface is in both monitor mode and promiscuous mode (those two settings can be orthogonal; don't assume that monitor mode implies promiscuous mode on your hardware/driver), but it sounds like you already took care of that.

Uncertain if this will help or is entirely correct but after some google searching this is what I arrived at.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .