Subject: Re: ath(4) and stealth AP
To: Rui Paulo <>
From: Sam Leffler <>
List: current-users
Date: 04/19/2006 09:56:56
Rui Paulo wrote:
> Sam Leffler <> writes:
>> Rui Paulo wrote:
>>> Tatoku Ogaito <> writes:
>>>> Hi,
>>>> I'm having a problem with the ath(4) device recently.
>>>> After the "Big update on ath and net80211",
>>>> both of my ath on pci (ThinkPad X31) and ath on cardbus cannot find
>>>> wireless network which provided by stealth Access Point.
>>>> Since wi(4) and iwi(4) can connect the same network at same time,
>>>> I think it is the problem on ath.
>>>> Also, when I change the AP setting to announce its SSID, ath CAN
>>>> connect to the network.
>>>> Has anybody else noticed any problem like this ?
>>> Not with ath, but with ral AND wpa_supplicant. It's unable to
>>> find the AP is SSID broadcast is off.
>> Is the channel marked for passive scan only?
> I think it was for active scan (if you mean scan_ssid=1), but I'm
> packaging and I already shut down the box..

Channels are marked passive according to local regulatory constraints. 
When scanning you're not supposed to send a probe req on a channel setup 
this way unless you know it's being used for 802.11 communication.  The 
code currently in cvs will listen on such channels but when the ap is 
not broadcasting it's ssid this is insufficient.

So was the ap setup on a channel marked for passive scan only?  In 
freebsd you can tell by doing

ifconfig ath0 list chan

and channels marked passive have a '*'.