Wireshark-users: Re: [Wireshark-users] R: R: R: Ipw3945 monitor mode
From: SamA <samuelapt@xxxxxxxxxxx>
Date: Mon, 16 Mar 2015 03:01:46 +0000 (UTC)
Joerg Mayer <jmayer@...> writes:

> 
> On Fri, Oct 26, 2007 at 05:53:49PM +0200, Massimo Palmeri wrote:
> > Joerg, thank you for your reply.
> > I fully agree with you. Probably I was not clear in exposing my 
problem:
> > wireshark shows me frames not only from adjacent channels, but also 
from
> > very far channels, such as channel 60.
> > My problem is how to tell ipw3945 driver to stop scanning and listen 
to a
> > single given channel.
> 
> I finally understand your problem. OK, I fully agree with you that 
this
> behaviour isn't correct. If you find a solution that would work using
> iwpriv or whatever please update the wiki or let us know so we may
> update the wiki. Your best bet would probably be to ask that question
> on the ipw3945 mailing list.
> 
>  ciao
>         Joerg


Hi,
This seems to be a very old thread but I hope someone managed to fix 
this back in 2007...

I have a very similar problem as is described in this text. I have a 
loop that scans first channel 1 (at 2.4GHz), then channel 2 and so on. 
Packets are captured for 5 seconds and stored in a pcap file (with 
dumpcap).

The problem is that when I see the same AP's popping up on adjacent 
channels. For example, scanning on channel 1 gives MAC X and MAC Y. Then 
I scan at channel 2 and the same MAC addresses are popping up again (but 
the radio tap header reports the correct channel numbers).

Have worked a lot with radio and this is not a correct behavior. Can see 
from the mail thread that channels overlap. This is true, but when you 
set a center frequency the receiver only looks for sync symbols coming 
in there. It doesn't look for sync symbols 5MHz away.

So something fishy is going on. Either packets are stuck in the cash in 
some way or there is some other fishy behavior. Would be very happy if 
someone has a remedy and can share that.

Thanks!
Sam