1.If an user knows the frequency used by a wireless network, is he able to collect the packets from that network? Those packets may be encrypted, but can he collect those packets?

2.If the user has a wireless card supporting the range of frequencies, what is the way to capture those packets?

3 Answers 3


The channel is broadcast as part of the wifi protocol, and most wifi cards have a "promiscuous mode" that allows them to listen too all traffic on a channel, regardless of which MAC address it's addressed to.

There's widely available software that's free that allows anyone to do this. Wireshark is a popular choice. If the traffic is encrypted, the password would have to be cracked (if possible) before the sniffed data could be decrypted.

There's no need to associate with the AP in any way, and it's not possible to detect someone sniffing network packets if done entirely passively.

  • To use Wireshark, does the user need to be in that network?
    – Vinay Raaz
    Jan 19, 2015 at 16:43
  • No, you don't need to associate with the AP in any way. Jan 19, 2015 at 16:47
  • If we know the credentials to establish a connection in that network, can we decrypt the encrypted packets? If we can decrypt, doesn't that make an attack without any trace left behind?
    – Vinay Raaz
    Jan 19, 2015 at 16:51
  • If you're using a pre-shared key and you capture the initial handshake you can decrypt the session and that can't be detected. If you're using Radius authentication I think the authentication password is different for each user, but I'm less familiar with Radius. Jan 19, 2015 at 17:01
  • I have checked wireshark. Even in promiscuous mode, it is capturing only from with in the network.if we are connected to no network,it simply doesn't capture anything.(wlan0)
    – Vinay Raaz
    Jan 20, 2015 at 11:49

Yes he could collect the packets while not being connected to the network. The packets would be encrypted if the network has a password on it.


Yes, as long as you've got the hardware to sniff a certain band, anything sent across that band (within range) can be captured. Hence the need for encryption.

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