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?

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

Reply to
NetSteady

Reply to
Teddybare

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.

Reply to
Teddybare

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.

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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.

Reply to
Jeff Liebermann

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)

Reply to
avirup_dasgupta

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.

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:
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'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.

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.

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.

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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?

Reply to
Jeff Liebermann

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