RE: monitor mode

Hi Suihong,

Unfortunately the firmware does not support monitor mode.
The "monitor" that iwpriv reports is a 'hacked up' quasi-monitor mode that I
added to the driver. What it lets you do is use any application (eg: Kismet,
Ethereal) with the WiFi adapter by fooling it into thinking it supports
proper full monitor mode (as if it would collect all WiFi frames on a given
channel). With this driver, the only information that gets sent through to
these apps are the management (probe/beacon/response/...) frames sent by
other cards and broadcasting APs (so software channel hopping actually does
nothing). Personally I still find this to be quite useful as I'm going to
put my adapter into a wok, and - volia - you get a Woktenna (some fun
experimentation).

The (x, y) numbers for "monitor" are:
(x) whether you want to enable monitor mode or not (0 - off, 1 - on & use
Prism frame headers (Kismet uses this, for example, to extract signal power
info, 2 - on but don't encapsulate in Prism headers), and
(y) the channel you want to listen to (1-14, but as I said has no effect
here).

The driver also supports the other method of setting monitor mode, which can
be done through "iwconfig <interface> mode Monitor". The "iwpriv" way is
simply for compatibility with apps such as Kismet.

To perform your ethereal logging, you'll actually have to connect to the
network you want to monitor first. Then you can use ethereal to log packets
as if you were connected to, say, a normal LAN. (i.e.: not including WiFi
encapsulation info, as you would get with proper monitor mode).

So sorry :) I recommend that you go and buy a proper PCMCIA WiFi card. If
you get any old rebadged Orinoco based card (I have an Avaya, but that's the
same as Cabletron, etc, etc...) it'll work wonders with Kismet, Ethereal,
Airsnort, etc. You can then purchase a pigtail if you wish and make a
cantenna (they're really quite fantastic, I've built two and now I'm
building a discone).

Hope this helped!
Balint

> -----Original Message-----
> From: [email protected] [mailto:at76c503a-user-
> [email protected]] On Behalf Of Suihong Liang
> Sent: Monday, 15 November 2004 10:11 AM
> To: [email protected]
> Subject: [at76c503a-user] monitor mode
> 
> Hi everyone,
> 
> I have questions about the monitor mode of atmel chipset. From iwpriv, I
> saw "monitor          (8BF2) : set   2 int   & get   0", does it mean
> monitor mode is supported by the firmware and driver?
> 
> However, I couldn't find useful information on using iwpriv to change the
> modes, could someone please explain the numbers (x, y) in "#iwpriv wlan0
> monitor x y"?
> 
> The last question is that I want to use ethereal to log the events of
> scan/authentication/association as well as the dhcp packets, how do I
> monitor all these?
> 
> Btw, my machine has Fedora 3 and Linksys WUSB11 v2.8. Any comments would
> be appriciated!
> 
> Thanks!
> suihong
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