Re: Some confusion about channels and frequencies

Douglas Almquist <[email protected]> writes:

> I have a Netgear WG511 card that I've been quite happy with now that I've 
> switched to a kernel that supports the card natively.
>
> I've been investigating security on my wireless net and have some questions 
> about channels and frequencies.
> Using iwlist, I get the following list of frequencies/channels that claim to 
> be supported...
>
> iwlist eth1 freq
> eth1      26 channels in total; available frequencies :
>           Channel 01 : 2.412 GHz
>           Channel 02 : 2.417 GHz
>           Channel 03 : 2.422 GHz
>           Channel 04 : 2.427 GHz
>           Channel 05 : 2.432 GHz
>           Channel 06 : 2.437 GHz
>           Channel 07 : 2.442 GHz
>           Channel 08 : 2.447 GHz
>           Channel 09 : 2.452 GHz
>           Channel 10 : 2.457 GHz
>           Channel 11 : 2.462 GHz
>           Channel 12 : 2.467 GHz
>           Channel 13 : 2.472 GHz
>           Channel 14 : 2.484 GHz
>           Channel 37 : 5.17 GHz
>           Channel 38 : 5.18 GHz
>           Channel 39 : 5.19 GHz
>           Channel 40 : 5.2 GHz
>           Channel 41 : 5.21 GHz
>           Channel 42 : 5.22 GHz
>           Channel 43 : 5.23 GHz
>           Channel 44 : 5.24 GHz
>           Channel 45 : 5.26 GHz
>           Channel 46 : 5.28 GHz
>           Channel 47 : 5.3 GHz
>           Channel 48 : 5.32 GHz
>           Current Channel=10
>
> However using a tool that comes with kismet, I get a very different list of 
> supported channels:
>
> listchan.pl eth1
> 1,2,3,4,5,6,7,8,9,10,11,12,13,14,34,36,38,40,42,44,46,48,52,56,60,64

The iwlist frequencies and the listchan channel numbers are correct.
The iwlist channes numbering is wrong.  Ref 802.11a, where

channel 34 = 5170 MHz
channel 36 = 5180 MHz
channel 38 = 5190 MHz
channel 40 = 5200 MHz
channel 42 = 5210 MHz
channel 44 = 5220 MHz
channel 46 = 5230 MHz
channel 48 = 5240 MHz
channel 52 = 5260 MHz
channel 56 = 5280 MHz
channel 60 = 5300 MHz
channel 64 = 5320 MHz


> I'm hoping someone can shed some light on this for me.

use frequencies, not channels


Bjørn