WLan visible but no IP address

I have a very strange problem with my WLAN-Router (Sinus 1054
DSL). So far I only used it with LAN, which is working just fine. I
just occasionally turned on the WLan when I had visitors. Then the
problem occured: The network was visible (and strong) but it was not
possible to connect (it did not give the laptop an IP address). This
happend with a number of notebooks under both linux and windows. All of
those visitors were computer geeks and checked the configuration of the
router, but everything was fine (different configurations were tried
(with, without encryption; with, without MAC-Filter), but nothing
worked.)

Now the strange thing happens: With one of these friends it suddenly
worked the next morning: I did not change the configuration of the
router nor did my friend change his settings. With another friend it
worked after changing the channel.

This kind of gives me the idea that maybe the WLan has some kind of
weird problem with another WLan, since that could explain the above
phenomenon. Anyway I never really tried to solve the problem, since I
did not have a laptop to use the WLAN for, until last week.
Now the same problem happens again, but switching the channel does not
work this time. Also the configuration of the notebook is fine, because
I can log on to another (someones :-)) network, which is much weaker.

I have absolutely no idea what else I could try - also it does not
sound like a hardware problem, because occasionally it does work. I am
also fairly certain that the configuration of the router is fine, since
I had independently different people (all of whom are computer experts)
check it because of the problem and noone could find anything wrong.

I would greatly appreciate any suggestions.

Best, moepmoep

The usual problems:
1. Radio interference.
2. MAC filtering in the router.
3. WEP key mismatch.
To troubleshoot, start by disabling *all* security.

On 28 Jul 2006 06:09:50 -0700, "moepmoep" <(E-Mail Removed)> wrote in
<(E-Mail Removed). com>:

>I have a very strange problem with my WLAN-Router (Sinus 1054
> DSL). So far I only used it with LAN, which is working just fine. I
>just occasionally turned on the WLan when I had visitors. Then the
>problem occured: The network was visible (and strong) but it was not
>possible to connect (it did not give the laptop an IP address). This
>happend with a number of notebooks under both linux and windows. All of
>those visitors were computer geeks and checked the configuration of the
>router, but everything was fine (different configurations were tried
>(with, without encryption; with, without MAC-Filter), but nothing
>worked.)
>
>Now the strange thing happens: With one of these friends it suddenly
>worked the next morning: I did not change the configuration of the
>router nor did my friend change his settings. With another friend it
>worked after changing the channel.
>
>This kind of gives me the idea that maybe the WLan has some kind of
>weird problem with another WLan, since that could explain the above
>phenomenon. Anyway I never really tried to solve the problem, since I
>did not have a laptop to use the WLAN for, until last week.
>Now the same problem happens again, but switching the channel does not
>work this time. Also the configuration of the notebook is fine, because
>I can log on to another (someones :-)) network, which is much weaker.
>
>I have absolutely no idea what else I could try - also it does not
>sound like a hardware problem, because occasionally it does work. I am
>also fairly certain that the configuration of the router is fine, since
>I had independently different people (all of whom are computer experts)
>check it because of the problem and noone could find anything wrong.
>
>I would greatly appreciate any suggestions.
>
>Best, moepmoep

--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>

Thanks, I did disable all security - that was the first thing I tried,
but without success. It must be radio interference then, because it was
the same thing again today. This morning I locked in and it did not
work, this evening I turned my laptop on and got into my wlan without
any problems. But I did neither change my notebook settings nor the
router settings.

Is there anything I can do to prevent the problem from occurring again?

Best,
moepmoep

John Navas wrote:
> The usual problems:
> 1. Radio interference.
> 2. MAC filtering in the router.
> 3. WEP key mismatch.
> To troubleshoot, start by disabling *all* security.

Try to find and eliminate the source of interference. Possible sources
are listed in the wikis below.

On 28 Jul 2006 15:02:36 -0700, "moepmoep" <(E-Mail Removed)> wrote in
<(E-Mail Removed) .com>:

>Thanks, I did disable all security - that was the first thing I tried,
>but without success. It must be radio interference then, because it was
>the same thing again today. This morning I locked in and it did not
>work, this evening I turned my laptop on and got into my wlan without
>any problems. But I did neither change my notebook settings nor the
>router settings.
>
>Is there anything I can do to prevent the problem from occurring again?
>
>Best,
>moepmoep
>
>John Navas wrote:
>> The usual problems:
>> 1. Radio interference.
>> 2. MAC filtering in the router.
>> 3. WEP key mismatch.
>> To troubleshoot, start by disabling *all* security.

--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>

moepmoep wrote:
> Thanks, I did disable all security - that was the first thing I tried,
> but without success. It must be radio interference then, because it
> was the same thing again today. This morning I locked in and it did
> not work, this evening I turned my laptop on and got into my wlan
> without any problems. But I did neither change my notebook settings
> nor the router settings.
>
> Is there anything I can do to prevent the problem from occurring
> again?
>
> Best,
> moepmoep

Just out of curiosity, does it work if you power the wap/router off and then
back on again? I was having probs with the speed dropping and dropping due
to interfernce from my neighbor, just a silly lamp timer on the power wall
wart to turn it off and back on again twice a day works for now ($3.49).. At
least twice a day I can restart the device and go back to full speed, other
times I just do a click/repair (for those lurking, not worth fixing, I
closed on a new place today and am moving this weekend.. No more neighbor
with his interference)

>
> Just out of curiosity, does it work if you power the wap/router off and then
> back on again?

No, I have tried that a couple of times, it did not work.

Is it possible to have that effect because of interference with another
WLan device. Since this one time, changing the channel helped (if it
was not a weird coincidence). Anyway, if it is anything like that the
problem will be solved in a couple of weeks, since I will be moving. :-)

John Navas wrote:
> Try to find and eliminate the source of interference. Possible sources
> are listed in the wikis below.
>

Thanks, I did that, but there is nothing listed that could cause the
problem and is in my flat. So I will just hope for the best, that it is
stable now and that the problem will solve itself once I moved.

Best wishes.

moepmoep wrote:
>> Just out of curiosity, does it work if you power the wap/router off
>> and then back on again?
>
> No, I have tried that a couple of times, it did not work.
>
> Is it possible to have that effect because of interference with
> another WLan device. Since this one time, changing the channel helped
> (if it was not a weird coincidence). Anyway, if it is anything like
> that the problem will be solved in a couple of weeks, since I will be
> moving. :-)

Sounds like a plan, hey I'm moving too.. matter of fact the movers are at
the door.. See ya!

"moepmoep" <(E-Mail Removed)> hath wroth:

>This kind of gives me the idea that maybe the WLan has some kind of
>weird problem with another WLan, since that could explain the above
>phenomenon.

The obvious cause is interference from another wireless LAN or other
source for RFI. See list at:
http://wireless.wikia.com/wiki/Wi-Fi#Interference

However, I don't think it's interference. I'm not familiar with a
Sinus 1054 DSL.
http://www.routerguide.org/index.php/Sinus_1054_DSL
Looks fairly generic. Linux based firmware.

You've already tried various other laptops and wireless clients.
However, you haven't tried replacing the wireless. If it really is
interference, a replacement unit will have the same problem. If you
can borrow a different router to try in place of the Sinus 1054 DSL,
then interference as a possible cause might be eliminated.

Another way to eliminate interference as a possible cause is to
isolate the router. Take the router and a laptop to some RF secluded
location. Underground basements are good. No change of any
interference there. Try connecting. If it works, it's interference.
If you have the same problem, it's a broken router.

My sense of smell points to a bad radio in the wireless router. In
this case, the transmitter is working because users can "see" the
router, but the receiver might be sick. Dunno.

Anyway, you said that you're moving so this is not really worth
spending much time trying to fix (unless you want to arrive at your
new location with the same problem).
--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Thanks for the long reply.

> My sense of smell points to a bad radio in the wireless router. In
> this case, the transmitter is working because users can "see" the
> router, but the receiver might be sick. Dunno.

But that also seems weird, because right now I am connected to the
router. As I said Thursday night and Friday morning it did not work,
but Friday night it worked and also today.

>
> Anyway, you said that you're moving so this is not really worth
> spending much time trying to fix (unless you want to arrive at your
> new location with the same problem).

I kind of hope it will keep working until then. If the problem remains,
then I will have to check thouroughly.

Best,
moepmoep