Is somebody blocking my wifi?

I've had a wireless access point since I got my Centrino notebook
fifteen months ago. The seperate 4 Port ADSL Router and 3Com WAP units
were replaced six weeks ago with a single device from Maplin (4 Port
Wireless ADSL Router!). If anything the signal was better than before,
not that it was bad before.

Then this morning, my notebook wouldn't detect the access point. I
troubleshooted by putting the notebook right next to the router,
resetting the router back to factory defaults and reinstalling from
scratch. Still couldn't find any hotspots so I returned the router to
maplin and they replaced it.

Got it home, set it up, and the problem remained. Then I had the bright
idea to switch the wireless RF channel on the router from CH6 to CH11.
Suddenly, it started working. It was fine throughout the afternoon.
Then at 6pm, all hotspots vanished again. Thinking my Centrino notebook
might be at fault (reception malfunction?), I switched off the integral
wireless (via a switch on the front) and plugged in a 3Com OfficeConnect
Wireless 11g PC Card that I kept hold of in case of emergency. That
wasn't finding any networks either. Then I switched the RF channel back
to CH6, and hey presto, it starts working again. And not only is the
3Com card finding it, but after removing it and enabling Centrino
wireless again, my notebook finds it too.

What's going on here? If other WAPs are operating on the same channel
in the neighbourhood, can that cause problems? Is it possible somebody
is being malicious and somehow jamming the signal? (Sounds paranoid,
but some local hotspots have identified themselves with some really
/interesting/ SSIDs just recently.)
--
Lee J. Moore
"Life is short, art is long."

LJM used his keyboard to write :
> What's going on here? If other WAPs are operating on the same channel
> in the neighbourhood, can that cause problems? Is it possible somebody
> is being malicious and somehow jamming the signal? (Sounds paranoid,
> but some local hotspots have identified themselves with some really
> /interesting/ SSIDs just recently.)

Try Netstumbler, it should be able to identify your own and other
access points operating in your local area. That assumes that your WiFi
chipset in the laptop is compatable, but most are.

--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.org

LJM wrote:

>
> What's going on here? If other WAPs are operating on the same channel
> in the neighbourhood, can that cause problems? Is it possible somebody
> is being malicious and somehow jamming the signal? (Sounds paranoid,
> but some local hotspots have identified themselves with some really
> /interesting/ SSIDs just recently.)



try netstumbler http://www.netstumbler.com/downloads/ to see whats
around and on what channels (turn your AP off first of course in case
they have set an identical SSID)

Friends, johnydeath, countrymen, lend me your newsreaders:
> LJM wrote:
>
>> What's going on here? If other WAPs are operating on the same
>> channel in the neighbourhood, can that cause problems? Is it
>> possible somebody is being malicious and somehow jamming the signal?
>> (Sounds paranoid, but some local hotspots have identified themselves
>> with some really /interesting/ SSIDs just recently.)
>
> try netstumbler http://www.netstumbler.com/downloads/ to see whats
> around and on what channels (turn your AP off first of course in case
> they have set an identical SSID)

Thanks (and to Harry as well). It seems to do the same as the Toshiba
Connectivity doctor, only that shows them more graphically (hotspots
slowly orbiting a notebook from various distances depending on their
range). Turned off my own AP, and Netstumbler didn't find anything with
the same SSID. When I turned my own AP back on, it reckoned it was
using WEP encryption though, which it 'aint. I've always used WPA.
(Winders and the Toshiba util correctly detect WPA.)

--
Lee J. Moore
"Life is short, art is long."

"LJM" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>
> Thanks (and to Harry as well). It seems to do the same as the Toshiba
> Connectivity doctor, only that shows them more graphically (hotspots
> slowly orbiting a notebook from various distances depending on their
> range). Turned off my own AP, and Netstumbler didn't find anything with
> the same SSID. When I turned my own AP back on, it reckoned it was
> using WEP encryption though, which it 'aint. I've always used WPA.
> (Winders and the Toshiba util correctly detect WPA.)
>


Netstumbler always reports WEP, its a problem with the program itself.

[snip]
> What's going on here? If other WAPs are operating on the same channel
> in the neighbourhood, can that cause problems? Is it possible somebody
> is being malicious and somehow jamming the signal? (Sounds paranoid,
> but some local hotspots have identified themselves with some really
> /interesting/ SSIDs just recently.)

What is an /interesting/ SSID? I, for example, use a random SSID (a real
jumble of hexadecimal characters) although I don't broadcast it either.

Paul DS.

In article <(E-Mail Removed)>,
>What's going on here? If other WAPs are operating on the same channel
>in the neighbourhood, can that cause problems? Is it possible somebody
>is being malicious and somehow jamming the signal? (Sounds paranoid,
>but some local hotspots have identified themselves with some really
>/interesting/ SSIDs just recently.)

You may find that someone nearby is using 2.4GHz for something else. Eg I
have a wireless TV extender, and it and the wireless access point tend to
interfere with each other quite a lot. Maybe a neighbour has installed
one, or some other device on 2.4GHz - that's the risk when devices use an
unregulated frequency band.

Zane.

Friends, Paul D.Smith, countrymen, lend me your newsreaders:
> [snip]
>> What's going on here? If other WAPs are operating on the same channel
>> in the neighbourhood, can that cause problems? Is it possible somebody
>> is being malicious and somehow jamming the signal? (Sounds paranoid,
>> but some local hotspots have identified themselves with some really
>> /interesting/ SSIDs just recently.)
>
> What is an /interesting/ SSID?

One local hotspot changes its SSID every other day. I'm fairly sure
it's the same one that's gone through these most rememberable SSIDs:

"Snotty Neighbour", "Bollocks Almighty" and "Fuck Fuck Fuck" (which
stands out inparticular because I didn't know until then that you could
have spaces in your SSID!). Somebody locally has too much time on their
hands.

> I, for example, use a random SSID (a real jumble of hexadecimal
> characters) although I don't broadcast it either.

Yep, I'm not broadcasting mine either. The Tosh hotspot detector
software still sees it but probably because it's configured to use it.
--
Lee J. Moore
"Life is short, art is long."

Friends, (E-Mail Removed) (), countrymen, lend me your newsreaders:
> In article <(E-Mail Removed)>,
>>What's going on here? If other WAPs are operating on the same channel
>>in the neighbourhood, can that cause problems? Is it possible somebody
>>is being malicious and somehow jamming the signal? (Sounds paranoid,
>>but some local hotspots have identified themselves with some really
>>/interesting/ SSIDs just recently.)
>
> You may find that someone nearby is using 2.4GHz for something else. Eg I
> have a wireless TV extender, and it and the wireless access point tend to
> interfere with each other quite a lot. Maybe a neighbour has installed
> one, or some other device on 2.4GHz - that's the risk when devices use an
> unregulated frequency band.

Thanks for the response. :-) Everything has been fine since last night
so I'll see what happens. I'm v.annoyed that I returned a AP/Router
combo though - when there was probably nothing wrong with it.
--
Lee J. Moore
"Life is short, art is long."

> > What is an /interesting/ SSID?
>
> One local hotspot changes its SSID every other day. I'm fairly sure
> it's the same one that's gone through these most rememberable SSIDs:
>
> "Snotty Neighbour", "Bollocks Almighty" and "Fuck Fuck Fuck" (which
> stands out inparticular because I didn't know until then that you could
> have spaces in your SSID!). Somebody locally has too much time on their
> hands.
>
> > I, for example, use a random SSID (a real jumble of hexadecimal
> > characters) although I don't broadcast it either.
>
> Yep, I'm not broadcasting mine either. The Tosh hotspot detector
> software still sees it but probably because it's configured to use it.
> --
> Lee J. Moore
> "Life is short, art is long."

Interesting. I wonder if they are running a "randomize SSID" type
application. I've seen programs that manage to change the SSID and WEP keys
regularly. I'm not sure how, or it, they synchronize the various clients
with the access point but the idea if to keep changing to avoid someone
sniffing for too long and cracking the secure channel.

Alternatively, perhaps they're having the same problem as you and this is an
attempt to indicate "stop messing up my wireless please..." is a very
visible manner ;-).

Paul DS.