unable to associate with wireless access point at home

qanopus · 03-09-2008, 06:57 AM

Hi,

I have dell E1505 laptop, which has a Intel PRO/Wireless 3945ABG card. I'm running slackware 12.0, with kernel 2.6.21. The device it self works fine under linux. Using the native driver (so not ndiswrapper) I can connect to wireless networks just fine.

Until about a week ago, everything was ok. But then suddenly, I started having trouble finding my wirless access point at home. Doing "/sbin/iwlist scan" I often cannot find the SSID belonging to my home connection. Under windows it shows up just fine. I have the following script to create a wireless connection:

Code:

#!/bin/bash

configfile=/etc/wpa_supplicant/wpa.conf
iface=eth1
driver=wext

if [ "$2" == "-v" ]; then
        optn=""
else
        optn="-B"
fi

start()
{
	echo "starting wireless service"
	/sbin/ifconfig $iface up
	/usr/sbin/wpa_supplicant -i $iface -D $driver -c $configfile $optn &  
	/sbin/dhclient eth1
	return 0 
}

stop()
{
	/sbin/ifconfig $iface down
	killall wpa_supplicant
	killall dhclient
	return 0
}

case "$1" in
	start)
		start
		;;
	stop)
		stop
		;;

	restart)
		stop
		start
		;;
	*)
		echo "usage wireless [start, stop, restart]"
		exit 1
esac

It used to work fine. These days, it's having trouble even finding my access point. It still works most of the time, with some trouble. But right now I can't find my wireless router at all.

So my question is, why do I have no troubles under windows and why suddenly do I have them under linux?

Help me please.

unSpawn · 03-09-2008, 08:02 AM

Quote:

Originally Posted by schatoor

suddenly, I started having trouble finding my wireless access point at home.

So what changed? Any (re)configuration on the machine or AP? Software updates?

Quote:

Originally Posted by schatoor

Doing "/sbin/iwlist scan" I often cannot find the SSID belonging to my home connection.

Any other APs near? I've experienced some channels do influence others. Does iwconfig (debug, status?) from when it's looking for your AP to successfully auth'ing show any clues?

qanopus · 03-09-2008, 08:29 AM

Quote:

So what changed? Any (re)configuration on the machine or AP? Software updates?

No kernel updates or anything like that. I keep installing new software, but I cannot think of anything that could cause something like this.

Quote:

Any other APs near? I've experienced some channels do influence others. Does iwconfig (debug, status?) from when it's looking for your AP to successfully auth'ing show any clues?

Yes there are several other AP's near. I must say that often my AP will show up, but then often also not. Just this morning, repeatedly looking for it didn't get me anywhere, while in windows I was able to find it no problem. But then later today, It showed up under linux as well.

That the hell?? Why so inconsistent?

unSpawn · 03-10-2008, 06:21 AM

Quote:

Originally Posted by schatoor

That the hell?? Why so inconsistent?

Maybe that question is a product of frustration, but trying to answer it w/o facts can only lead to speculation IMHO. I'd start by using the commandline iw* tool to gather verbose details from when it's looking for your AP to successfully auth'ing.

qanopus · 03-11-2008, 04:50 PM

It seems that getting closer to the AP helps. The AP is in another room.

But how come windows can pick up the signal without much problem, while under linux I need to move closer?

unSpawn · 03-11-2008, 06:42 PM

You keep asking questions that compare ClippyOS with GNU/Linux but not supplying any data to work with. That doesn't help us to help you. You know perfectly well a lot of vendors see absolutely no market in GNU/Linux. So the fact a lot of drivers *just work* is not a tribute to standards, vendors or whatever but only to those who managed to hack a driver together.

qanopus · 03-12-2008, 03:46 AM

Quote:

So the fact a lot of drivers *just work* is not a tribute to standards, vendors or whatever but only to those who managed to hack a driver together.

Dude why the hostility? When did I even hint at what you are implying with the above? I'm not implying windows ( or "clippyos" ) is in anyway better, I'm just trying to tell you that it should be physically possible to get a wireless connection going. Why the hell am I getting attitude from you??

I know I should give you all the information possible but I just don't know what to do next. I just don't even know where to begin. Should I change something in the AP to get it to make the signal stronger? Should I report the signal strenth I'm getting in my room? Should I update the driver. Change the kernel? Are there any log files I can look at? Any config files I should edit?

I rarly ever come to this forum anymore because I mostly am able to figure out problems on my own. But this time I'm stuck. So can you please help me?!

If it helps anything, here is the output of iwlist scan with my AP (finally) on it.

Code:

eth1      Scan completed :
          Cell 01 - Address: 00:14:7F:40:29:98
                    ESSID:"SpeedTouch*****"
                    Protocol:IEEE 802.11bg
                    Mode:Master
                    Channel:1
                    Encryption key:on
                    Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s
                              11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s
                              48 Mb/s; 54 Mb/s
                    Quality=77/100  Signal level=-57 dBm  Noise level=-57 dBm
                    IE: WPA Version 1
                        Group Cipher : TKIP 
                        Pairwise Ciphers (2) : CCMP TKIP 
                        Authentication Suites (1) : PSK  
                    IE: IEEE 802.11i/WPA2 Version 1
                        Group Cipher : TKIP 
                        Pairwise Ciphers (2) : CCMP TKIP 
                        Authentication Suites (1) : PSK  
                    Extra: Last beacon: 32ms ago

Do you need more info? Just tell me what to give you.

unSpawn · 03-12-2008, 07:58 AM

Let's dissect the situation:
0. "It Just Works" in Windows,
1. it works intermittently in GNU/Linux,
2. behaviour changed at a defined point in time,
3. symptoms are not finding SSID.

The situation seems one-sided, behaviour changed at a distinct point in time so there is a starting point looking for changes: "about one week ago". So let's ask questions that try to find out what changed over time:

Questions:
0. So what changed?: answer incomplete,
1. (re)configuration on the machine?: not answered at all,
2. (re)configuration of the AP?: not answered at all,
3. Software updates?: answer not complete,
4. Any other APs near?: answer incomplete,
5. Does iwconfig (<- should be wpa_cli) (..) show any clues?: not answered at all.

Additions:
0. "It seems that getting closer to the AP helps. The AP is in another room",
1. Output showing WPA_PSK (TKIP) usage.

Quote:

Originally Posted by schatoor

I know I should give you all the information possible but I just don't know what to do next. I just don't even know where to begin.

What I get from the answers is the kernel wasn't updated, there was SW installed (but no 'find -mtime' output, no changed/installed package listing) and there are other AP's near (but no chan/freq listing), and moving closer to the AP seems to help. So no indication of what changed over time, no indication of (re)configuration was given for machine and AP, no wpa_cli status output or other information was given for comparison.

Quote:

Originally Posted by schatoor

Why the hell am I getting attitude from you?

The summary above shows that while you where gabbing on about inconsistencies and such I've been waiting for facts I can deal with. And I've gotten way less than I may expect from a senior member. Your response trying to shoot the messenger IMHO is uncalled for. If you however feel it's you who has been maligned by me just asking me to abandon this thread should do, NP.

Quote:

Originally Posted by schatoor

Should I change something in the AP to get it to make the signal stronger?

Like I said before there are many things that influence Wifi ranging from APs in other channels that interfere with your channel to the direction of the antenna (since the signal has no direct line of sight and has to pass through a wall) to (like you've found out) the placement of the laptop (IOW its antenna). Usually vendors ship APs with transmit strength set to max so I doubt that would change anything but do as you please.

Quote:

Originally Posted by schatoor

Should I report the signal strenth I'm getting in my room?

Link quality as reported looks OK. If it now works OK, the only thing that would make sense then would be to compare connection details with those from a successful connection in the spot your laptop was in originally.

Quote:

Originally Posted by schatoor

Should I update the driver.

Since you use Ndiswrapper then if you updated the driver in Windows you should, else there wouldn't be a driver to update, right? For the Intel PRO/Wireless 3945ABG you could try the GNU/Linux native Intel-tested http://downloadmirror.intel.com/1031...fi-1.0.0-1.tgz driver though.

Quote:

Originally Posted by schatoor

Change the kernel?

While new kernels incorporate fixes (which is a good thing), since it worked "one week ago" I don't think that'll matter much.

Quote:

Originally Posted by schatoor

Are there any log files I can look at?

Because you *can* connect to me that indicates there's no problem with the kernel or driver. The next parts that interact with Wireless will be iwconfig, ifconfig, iwconfig, wpa_supplicant and dhclient. The device can be brought up OK so that means both ifconfig and iwconfig supplied the right information, you *can* connect succesfully so that means wpa_supplicant.conf contains the right information and you get a lease. Like I said before the only thing that shows the conversation between your machine and the AP is wpa_cli. Might as well bring wpa_supplicant up in verbose/debug mode too to squeeze out any drop of information that could hold a clue.

Quote:

Originally Posted by schatoor

Any config files I should edit?

At this point I see no cause for editing config files. (I mean, what would you change?)

qanopus · 03-12-2008, 08:24 PM

Okey so lets stop biting each others head off and get on with it then.

Quote:

0. So what changed?: answer incomplete,
1. (re)configuration on the machine?: not answered at all,
2. (re)configuration of the AP?: not answered at all,
3. Software updates?: answer not complete,
4. Any other APs near?: answer incomplete,
5. Does iwconfig (<- should be wpa_cli) (..) show any clues?: not answered at all.

0 & 3. I told you, nothing from my end. I did install software, things like matlab, maple and other scientific software like gdl (http://gnudatalanguage.sourceforge.net/) and dependancies like GConf, matplotlib, numarray and ORBit. I did try to install "networkmanager" but not only was this in response to the problem i'm dealing with here (so installing that could not be the cause of the problem), the installation failed because of dependancy issues. I also installed the mplayer firefox plugin.
And I changed nothing in my hardware.
1 & 2. Do you really think that I woulden't mention that if I had??

4. Okey, I admit, I should of listed more completly. The thing is, because the problem is not very reproducable, I can't just give you the output of iwlist now (I associated with my AP just fine just now). I'll have to wait for the problem to occure again and see if there are possible interferences.

5. wpa_cli ? I didn't know this program even existed. I will check out it's man page to figure out how to work it.
I also admit I should probebly have played a bit with iwconfig to see if I could get an association like that. Maybe it will report error's whch can help solve the problem.

Like I said, it has little use to do all of this now. I'll wait until the problem reoccures and we will take it from there.

Quote:

Since you use Ndiswrapper ...

I said in my first post I'm not using ndiswrapper, but the linux native driver.
That said, maybe I should try that.

Quote:

Because you *can* connect to me that indicates there's no problem with the kernel or driver. The next parts that interact with Wireless will be iwconfig, ifconfig, iwconfig, wpa_supplicant and dhclient. The device can be brought up OK so that means both ifconfig and iwconfig supplied the right information, you *can* connect succesfully so that means wpa_supplicant.conf contains the right information and you get a lease. Like I said before the only thing that shows the conversation between your machine and the AP is wpa_cli. Might as well bring wpa_supplicant up in verbose/debug mode too to squeeze out any drop of information that could hold a clue.

Thank you, that is useful. I will give wpa_cli a go if the problems occurs again and bring wpa_supplicant to verbrose mode (forgot all about that).

Thanks, your help is appreciated.

qanopus · 03-12-2008, 09:21 PM

Reading your post in more detail, I see that you are linking to a different driver then the one I use. I use the driver "ipw3945" and it seems you are refering to "iwlwifi". If nothing else works, I'll try that driver.

Thanks again.

unSpawn · 03-13-2008, 06:25 AM

Quote:

Originally Posted by schatoor

I said in my first post I'm not using ndiswrapper, but the linux native driver.

Aw. Must have read over that. Sorry.

Quote:

Originally Posted by schatoor

Like I said, it has little use to do all of this now. I'll wait until the problem reoccures and we will take it from there.

NP, just post here if it happens in a week from now or else create a new thread linking to this one once you encounter probs and we'll take it from there. Might be good to familiarise yourself with wpa_cli output and save some of that as reference so you know what "good" output looks like.

esm_menc · 03-15-2008, 03:33 AM

Only time I had connect problems.. my neighbor kept jumping channels and trying to use my channel which would then show his ap because his router and range extender beat my routers power output. so i just had a chat with him... no problems now.
I knew i was on ch 8 he was on 1-2-4-6-8-11 etc. said he was just trying to set it up. thought my router went out at first. (i dont use clippy)