Is there any way we would be able to detect which devices/laptops in a wlan are using 802.11b & which are using 802.11g cards? 802.11b clients in 802.11g wlan

Is there any way we would be able to detect which devices/laptops in a
wlan( with one 802.11g AP) are using 802.11b & which are using 802.11g
cards?

<avirup_dasgupta@indiatimes.com> wrote in message
news:1127109226.227025.199630@g44g2000cwa.googlegr oups.com...
> Is there any way we would be able to detect which devices/laptops in a
> wlan( with one 802.11g AP) are using 802.11b & which are using 802.11g
> cards?
>

<avirup_dasgupta@indiatimes.com> wrote in message
news:1127109226.227025.199630@g44g2000cwa.googlegr oups.com...
> Is there any way we would be able to detect which devices/laptops in a
> wlan( with one 802.11g AP) are using 802.11b & which are using 802.11g
> cards?
>

Yes, turn off the 801.11 b support in the router. All the Gs will connect
and the Bs will complain about the loss of connection.

What type of device? Some of the more sophisticated enterprise systems
do this today. However, some of the lower end one's dont.

On 18 Sep 2005 22:53:46 -0700, avirup_dasgupta@indiatimes.com wrote:

>Is there any way we would be able to detect which devices/laptops in a
>wlan( with one 802.11g AP) are using 802.11b & which are using 802.11g
>cards?

Sure. The status page on most of the better wireless routers will
display the connection speed. If you have command line access to the
wireless routers, diagnostic commands such as "wl" will deliver both
the connection status and the capeabilities of the client.
http://www.linksysonline.com/content/view/31/44/
The speed information and more are transmitted in the 802.11 managment
packets and are also available to anyone with a passive sniffer such
as Kismet.

For more detail, kindly disclose what you're trying to accomplish and
what you have to work with.


--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Thanks for the answers,

"The speed information and more are transmitted in the 802.11 managment
packets and are also available to anyone with a passive sniffer such as
Kismet. "

If i user sniffer, what will i look for in packets which will determine
whether it's a b client Or g client. Will it be the protection bits?

" G APs announce whether Protection is required by setting a flag in an
"ERP Information Element" included in Beacon and Probe Response
packets. In the absence of B stations, the AP sets Use_Protection = 0
so that G stations can operate with greater efficiency. If the AP sets
Use_Protection = 1, all G stations must immediately begin using
Protection mechanisms to politely share the channel with B stations. "


Another question,is it possible to determine from mac address whether
its a b or g client( like we can do for vendor name)

On 20 Sep 2005 03:30:40 -0700, avirup_dasgupta@indiatimes.com wrote:

>Thanks for the answers,

Thanks for not answering what you're trying to accomplish and what you
have to work with. I'll assume you're working for a secret government
agency and such information must be withheld.

>"The speed information and more are transmitted in the 802.11 managment
>packets and are also available to anyone with a passive sniffer such as
>Kismet. "
>
>If i user sniffer, what will i look for in packets which will determine
>whether it's a b client Or g client. Will it be the protection bits?

No. It will be from the modulation type.

First, you need to download and dig through the 802.11, 802.11b and
802.11g standards at:
http://standards.ieee.org/getieee802/802.11.html
It's quite a bit of heavy reading but it's all in there.

In 802.11g, you'll find "extended support rates", "Extended Rate PHY
Specification" and "Capability Information" fields in the management
frames. You'll find the list of acceptable data rates (section
10.4.4.2) along with the modulation code. The modulation code is the
clue. If it's DSSS-OFDM, then it's 802.11g. If it's anything else,
it's 802.11 or 802.11b.

You can sniff and decode this stuff with Ethereal and the associated
802.11 decoder. However, you'll have some difficulties finding a
wireless adapter that will do the necessary promiscuous mode under
Windoze. I therefore suggest you do your sniffing with Linux.

>" G APs announce whether Protection is required by setting a flag in an
>"ERP Information Element" included in Beacon and Probe Response
>packets. In the absence of B stations, the AP sets Use_Protection = 0
>so that G stations can operate with greater efficiency. If the AP sets
>Use_Protection = 1, all G stations must immediately begin using
>Protection mechanisms to politely share the channel with B stations. "

I think that's just the flag used to notify the other clients that
there is an 802.11b client in the system and that they should shut up
long enought for ever so slow 802.11b client to get it's traffic
through. You could have the flag set, and have all the 802.11g
clients running 802.11g.

>Another question,is it possible to determine from mac address whether
>its a b or g client( like we can do for vendor name)

Yes, but you would need to have a list of every manufacturers
equipment list and corresponding MAC addresses. That would also
assume that users are not spoofing their MAC addresses as it's very
easy to fake the MAC address.
http://www.klcconsulting.net/smac/
Actually, it also assumes that manufacturers don't re-use addresses or
use unregistered addresses, which I suspect may be happening.

As I asked before.... What are you trying to accomplish and what do
you have to work with?


--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558