Thread: capturing beacon frames on my wireless card

  1. #1
    Registered User
    Join Date
    Aug 2010

    capturing beacon frames on my wireless card

    Hi all,

    I have a wireless (802.11b) router Access Point and my laptop connected together. As i can see in the configuration of the router there should be a beacon frame sent every 100ms on my AP. I would like to see all these control,management frames sent from the AP to the stations.

    Now, in order to see those packets I need to set my wireless card on monitor mode and hope the the drivers that i have for the wireless card can give me this information. I have used tcpdump and wireshark to capture that but in both cases i couldnt see any of these frames.
    Here is what i ve tried.
    First wireless card

    Bus 001 Device 002: ID 050d:905b Belkin Components F5D9050 ver 3 Wireless Adapter

    in tcpdump i check my devices by
    sudo tcpdump -D
    7.any (Pseudo-device that captures on all interfaces)

    My Usb card is wlan2, and it also introduced the wmaster1 entrance in this command, not sure about the meaning of that. Next i tried to set my card in monitor mode
    sudo tcpdump -I wlan2

    or sudo tcpdump -I wmaster1

    in both cases the output is
    tcpdump: eth0: That device doesn't support monitor mode

    Because i couldnt find a solution for that, i move to wireshark and try to set the cards to capture the frames. In wireshark, capture interfaces i can see that the usb1 interface (the one i have my wireless card connected to) is adding up received packets. If i receive this packets the output is something like below which i do not understand.


    Second thing that i tried with wireshark is to set the interface of wmaster1 disabling the option of "hide capture info dialog" and from "Edit/preference/protocols" i set it to 802.11 frames.

    In this case i am able to see some 802.11 packets sent with no data from the Computer to the AP but they have no major meaning. Also it might worth to mention that i never see a packet sent from the AP mac origin to the Pc with no data value (which could be some controlling packet).

    So could somebody guide me what i am doing wrong?


  2. #2
    Registered User
    Join Date
    Aug 2010
    So far, all i can say is that the network cards do not support monitoring mode and therefore you can not see other packets nor frame values. Next time I ll have to double check before getting a wireless card


Popular pages Recent additions subscribe to a feed

Similar Threads

  1. Bitwise Unwanted Output
    By pobri19 in forum C++ Programming
    Replies: 4
    Last Post: 09-15-2008, 04:07 AM
  2. Vector out of range program crash.
    By Shamino in forum C++ Programming
    Replies: 11
    Last Post: 01-18-2008, 05:37 PM
  3. Segmentation Fault - aaaaaaaah!
    By yogibear in forum C Programming
    Replies: 6
    Last Post: 10-01-2007, 03:21 AM
  4. Blackjack
    By Tommo in forum C Programming
    Replies: 10
    Last Post: 06-20-2007, 08:07 PM
  5. How can I access a struct (from a header file)?
    By loxslay in forum C++ Programming
    Replies: 3
    Last Post: 10-07-2006, 01:25 PM