wireless connection at home

[George N. White III]

On Sat, 19 Apr 2008, Chris Kottaridis wrote:

> I have a Del Inspiron 1510 laptop running Fedora Core 8. I copied down
> the b43 driver for it and it does seem to get recognized OK. However,
> when I try to connect to an access point I can't seem to get it to
> connect. The iwconfig output always shows Link Quality: 0:
>
> $ iwconfig wlan0
> wlan0     IEEE 802.11  ESSID:"qwind-chrisk"
>          Mode:Managed  Frequency:2.447 GHz  Access Point:
> 00:0D:88:AC:A8:2C
>          Tx-Power=27 dBm
>          Retry min limit:7   RTS thr:off   Fragment thr=2352 B
>          Link Quality:0  Signal level:0  Noise level:0
>          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
>          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

What about "iwlist scan <interface>"?

> There was one time when I used the network manager to try and activate
> the card and it actually worked! The network manager counted it as
> successful and an ifconfig of the wlan0 showed that the card had sent 10
> packets and received 12. It had the ip address from the access point via
> dhcp. However, by the time I checked iwconfig to see the "Link Quality"
> it was 0 and nothing was getting transferred.

I had wireless working in F6+F7, but in F8 getting a connection at all
was problematic.

> I went to a local computer store because I thought maybe the card was
> bad. When I got there I had no problem activating the card and picking
> up an IP address from their access point in the store. Also the "Link
> Quality" said 86/100. So, I don't think there is an underlying hardware
> problem.
>
> So, I came back home and kept trying various combinations, setting a key
> on the access point, taking the key off, trying different channels,
> every possible thing I can think of. from looking at the iwconfig
> options and network manager options.  My wife's laptop and my 2 kid's
> laptops running Windows all connect up fine to the local access point.
>
> In the environment here I have about 4 wireless access points in the
> house behind various firewalls and VPN's. They are all clustered
> together in the same place. The DSL modem has wireless capability, the
> cisco router that provides VPN to my office has wireless, I have a
> "LinkSys Wireless G" that is what my wife and kids connect up to, and I
> put back into service a "D-link DWL -2000AP" access point I have to try
> and test this so I wouldn't disrupt the wife and kids connectivity as I
> tried different combinations on the access point. I have never done any
> configuration on any of them except the "LinkSys Wireless G" that my
> family uses, (and in the last couple of days on the D-link I reactivated
> in order to try some testing). So, I don't know if they are causing
> confusion to the card or not. However, when this exact machine was
> running Windows it connected up to the "LinkSys" access point just fine
> in this environment. The other laptops running Windows in the house have
> no trouble connecting to either the LinkSys or the newly activated
> D-link.

You should see all your AP's (and probably those of your neighbors) with a 
scan.  That is what I had with F6+F7, but with F8 I usually see nothing,
and on rare occasions I see the AP in my house.

> So it seems like it works fine in other environments (at least at the
> computer store), but in my home it doesn't, but did for a short time
> work once at home long enough to DHCP down an IP address. I have been
> trying every combination I can think to try and still can't seem to get
> anything but a link Quality of 0.
>
> Any advice or recommendations would be appreciated.

You should check the configurations of your AP's.  They should be much
more "locked down" than the ones in "public" sites.  For debugging you
want to "open up" your AP temporarily and use a manual wpa_supplicant
configuration (disable NetworkManager, enable wpa_supplicant or just
start it from a command line).  You may have to use WEP (which only
serves to announce that you aren't willing to provide a public AP) and 
rely on hardware mac address filtering to block casual intruders.

-- 
George N. White III  <aa056 at chebucto.ns.ca>