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kwesadilo 07-25-2008 02:18 PM

WPA - can't authenticate unless physically close to access point
 
I'm running Ubuntu 8.04 on a Thinkpad T61p with this wireless card. My wireless access point is an Actiontec MI424WR provided by Verizon. My problem is that I can only associate with the network using WPA when the computer is very close to the router. I have searched around on Google and various forums, but I only found one person with a somewhat similar problem, and he ended up having to get a new router, which isn't an option for me.

When I set this router to provide an unsecured wireless network, I can join and use the network on my laptop from anywhere in my house. I estimate that the straight line distance between my computer and the access point never exceeds 40 ft. and that the number of walls or floors between between the computer and the AP is never more than 3.

If I set the router to use WPA (AES-PSK), which is what I want to do, I cannot join the network unless the computer is fairly close to the AP (about 10 feet seems to be the maximum distance). If I am farther away than that, Network Manager repeatedly asks me for my network key, which I type in correctly to no avail. However, once I have authenticated with the AP, I can carry my computer to any other part of the house and still use the network (as long as I don't close the case, which would cause me to disconnect). From the locations where I cannot authenticate, I can see the wireless network in Network Manager with signal strength varying according to my location but never negligible.

Sometimes, I will try to connect using WPA from a greater distance, and I will connect successfully, only to drop the connection a second after it is made. This happens very occasionally within the Circle of Success as well.

I have also tried configuring the router for WEP. I was only able to connect to the network after many failed attempts, even within the Circle. When I did connect, I experienced the same problem as with WPA: I can move all over the house, but I can only connect from within the Circle.

Several other data points: The same computer in the same location running Windows XP Pro SP2 (with ThinkVantage connection software) connects to the WPA network without a hitch. So does a Dell Inspiron 6000 running XP Pro SP2 (stock). The Inspiron previously worked with WEP and no security using the same router. An Apple iBook G4 running OS X 10.3 and another one running 10.4 both had frequent WPA authentication problems, but these did not appear to be distance-related. I do not remember doing any extensive testing with any system other than the one that I am using now, Ubuntu on the Thinkpad.

I have tried putting a parabolic reflector on the AP's antenna to boost the signal in my direction, but that didn't help. I have tried manually configuring Network Manager, using both DHCP and a manual IP configuration, but that didn't work either.

So if anybody knows what's going on, I'd appreciate them sharing with me. I guess it's not the end of the world if it's my router's fault, because I'll be heading off to college in a month and leaving said router behind. But by that same token, I can't afford to take a computer to college that might have trouble with the campus network.

Edit: Here's one other weird thing that it does that may be related. Sometimes when I pull down a list of wireless networks in Network Manager, I see not only my home network but another. Usually, it is named default, and it has no security, but once it was just a bunch of letters and numbers, and it had 128-bit WEP. I thought that one might have been my neighbor's except that it showed full signal strength (stronger than the wireless router right next to me), and he lives like 500 ft. away. Usually, default is at or close to 100% signal strength, but one time it was 0%. I have never had any success in joining default. When I can see this network in Network Manager, I cannot see it on another laptop (whose wireless usually works). What do you think is going on?

jolphil 07-28-2008 07:17 AM

Hello,
I do not know what your problem is, but after reading your post, either I missed it or you failed to mention if you tried to change the channel number..
It would be worth a try and also would you post the tx and rx signal values
from a reasonable distance ..That way someone could compare results..
BTW I use WEP from my AP in my house with a parabolic antenna on each, and connect from a distance of over 200 feet to my garage computer..Thus I think you should be able to go 40 feet without issues..I am not an expert but thats just my perspective..
Goodluck,
jolphil:twocents:
Edit: have you tried to google"ubuntu wireless how to"?? There are lots of troubleshooting pages from Ubuntu to read..

Edit again:Just to give you some perspective, here are the results of my garage computer 200 ft. away..Take note of the link quality (signal to noise)using WEP encryption.
iwconfig as root
lo no wireless extensions.

sit0 no wireless extensions.

wifi0 no wireless extensions.

ath0 IEEE 802.11g ESSID:"xxxxxxxx" Nickname:"xxxxxx"
Mode:Managed Frequency:2.417 GHz Access point 00:18:E7:02:4B:E7
Bit Rate:54 Mb/s Tx-Power:18 dBm Sensitivity=0/3
Retry:off RTS thr:off Fragment thr:off
Encryption key:xxxxxxxxxxxxxxxxxxxx Security mode:open
Power Management:off
Link Quality=28/94 Signal level=-64 dBm Noise level=-92 dBm
Rx invalid nwid:1010 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0

kwesadilo 07-29-2008 11:17 PM

I messed around with it a bit
 
I noticed shortly after I first posted that I can no longer connect to the WPA network even when I'm close to the access point. I get the same thing as before where I get the password prompt over and over again.

I tried changing the channel of the network. I went through 1, 6, and 11, but nothing changed. Then I figured that as long as I'm changing stuff, I might as well try it without WPA, so I did. When I went to connect, I couldn't even see a wireless network in Network Manager. Rebooting the router didn't make the network appear, so I tried rebooting my computer into Windows XP Pro. I still couldn't see the network, so I got out a Dell Inspiron 6000 running XP Pro. That computer was able to get on the network, so I thought maybe my wireless card had died. I turned the card on and off via the hardware switch a couple of times and also rebooted the router again, but I still couldn't see the network. I booted back into Ubuntu, connected to the router via the wired network, and turned WPA changed the channel to 6. (It was originally 1, and I had left on 11 at the end of the channel test.)

I looked in Network Manager, and I could see the network again, so I tried connecting to it (from the 40-feet-away location). It gave me the password prompt, so I thought at least it was back to normal. I entered my password, and after a minute it spat the prompt back at me as usual. I didn't have any other bright ideas, so I entered my password in again and ... it worked! The prompt didn't come back up, and I had an IP address and everything. After some celebratory iwconfig-ing (more on that later), I went to sleep. The next morning (this morning), I again tried to join the network from 40 feet away, and, after a few password prompts, I was able to connect and browse the Web. A few hours later, I lost my network connection. I tried to join again, but it didn't work. I tried joining from close to the router, but that didn't work either.

I then turned off WPA. I wasn't able to see the network from 40 ft, but I went closer and was able to connect to it after the second attempt.

Here are the outputs of iwconfig in various locations. They are all from when I was connected to the network with WPA last night. Distances and number of intervening walls/floors are approximate. I've omitted the interfaces that have "no wireless extensions."

6 ft, 0 walls/floors
Code:

ath0      IEEE 802.11g  ESSID:"*****"  Nickname:""
          Mode:Managed  Frequency:2.437 GHz  Access Point: 00:18:01:E6:05:C5 
          Bit Rate:11 Mb/s  Tx-Power:8 dBm  Sensitivity=1/1 
          Retry:off  RTS thr:off  Fragment thr:off
          Power Management:off
          Link Quality=58/70  Signal level=-35 dBm  Noise level=-93 dBm
          Rx invalid nwid:1743  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0  Missed beacon:0

13.5 ft, 1 wall
Code:

ath0      IEEE 802.11g  ESSID:"*****"  Nickname:""
          Mode:Managed  Frequency:2.437 GHz  Access Point: 00:18:01:E6:05:C5 
          Bit Rate:11 Mb/s  Tx-Power:8 dBm  Sensitivity=1/1 
          Retry:off  RTS thr:off  Fragment thr:off
          Power Management:off
          Link Quality=43/70  Signal level=-55 dBm  Noise level=-98 dBm
          Rx invalid nwid:1744  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0  Missed beacon:0

37 ft, 2 walls/floors
Code:

ath0      IEEE 802.11g  ESSID:"*****"  Nickname:""
          Mode:Managed  Frequency:2.437 GHz  Access Point: 00:18:01:E6:05:C5 
          Bit Rate:11 Mb/s  Tx-Power:8 dBm  Sensitivity=1/1 
          Retry:off  RTS thr:off  Fragment thr:off
          Power Management:off
          Link Quality=24/70  Signal level=-73 dBm  Noise level=-97 dBm
          Rx invalid nwid:1744  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0  Missed beacon:0

35.5 ft, 2 walls/floors
Code:

ath0      IEEE 802.11g  ESSID:"*****"  Nickname:""
          Mode:Managed  Frequency:2.437 GHz  Access Point: 00:18:01:E6:05:C5 
          Bit Rate:12 Mb/s  Tx-Power:8 dBm  Sensitivity=1/1 
          Retry:off  RTS thr:off  Fragment thr:off
          Power Management:off
          Link Quality=34/70  Signal level=-63 dBm  Noise level=-97 dBm
          Rx invalid nwid:1744  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0  Missed beacon:0

30.5 ft, 3 walls/floors
Code:

ath0      IEEE 802.11g  ESSID:"*****"  Nickname:""
          Mode:Managed  Frequency:2.437 GHz  Access Point: 00:18:01:E6:05:C5 
          Bit Rate:5 Mb/s  Tx-Power:8 dBm  Sensitivity=1/1 
          Retry:off  RTS thr:off  Fragment thr:off
          Power Management:off
          Link Quality=19/70  Signal level=-79 dBm  Noise level=-98 dBm
          Rx invalid nwid:1744  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0  Missed beacon:0

Here is the output of iwconfig when I tried to join the mysterious "default" network that sometimes appears at 100%.
Code:

ath0      IEEE 802.11g  ESSID:"default"  Nickname:""
          Mode:Managed  Frequency:2.462 GHz  Access Point: Not-Associated 
          Bit Rate:1 Mb/s  Tx-Power:8 dBm  Sensitivity=1/1 
          Retry:off  RTS thr:off  Fragment thr:off
          Power Management:off
          Link Quality=127/70  Signal level=0 dBm  Noise level=-93 dBm
          Rx invalid nwid:172  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0  Missed beacon:0

Here is the iwconfig output when I was associated with the WPA network but not authenticated. I'm not sure how this happened. It had stopped prompting me for the password, but when I used ping, I got "Network unreachable."
Code:

ath0      IEEE 802.11g  ESSID:"*****"  Nickname:""
          Mode:Managed  Frequency:2.437 GHz  Access Point: 00:18:01:E6:05:C5 
          Bit Rate:54 Mb/s  Tx-Power:8 dBm  Sensitivity=1/1 
          Retry:off  RTS thr:off  Fragment thr:off
          Power Management:off
          Link Quality=62/70  Signal level=-33 dBm  Noise level=-95 dBm
          Rx invalid nwid:172  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0  Missed beacon:0

Here's the ifconfig output for that same situation.
Code:

ath0      Link encap:Ethernet  HWaddr 00:1f:e1:cc:6a:bf 
          inet6 addr: fe80::21f:e1ff:fecc:6abf/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:10 errors:0 dropped:0 overruns:0 frame:0
          TX packets:21 errors:15 dropped:15 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:1089 (1.0 KB)  TX bytes:1767 (1.7 KB)

I just now changed it back to WPA, and I was able to connect right up from 35 feet away. Maybe my machines are possessed.

jolphil 07-30-2008 09:05 AM

Hello again,
I noticed from your data that your transmitted power is weak..8dbm as compared to around 18dbm(see my data) this would account why you have a low bit rate and poor distance.. That means your router may be flawed or the antenna is somehow damaged..You may have to invest in a new one if you cannot figure out why it's so weak..Thats all I can think of now..
Goodluck,
jolphil
Edit: You might try a live cd of linux to see if your performance and bit rate or distance improves or not..I have had reasonably good luck with pclinuxos or mandriva but others may suggest differently..If anyone can help please jump in and offer suggestions..
jolphil

aws0 07-31-2008 10:45 AM

Hi guys

So nice to see that I'm not alone with this problem and I have some interesting info for you. I'm familiar with the exact behavour you guys explains. Bought a cheap laptop from HP (HP 530) and installed ubuntu Hardy. I have a Netgear router running at home WNR854T and works very good with my other laptops, one running WinXP and one running Win Vista.

The ubuntu computer is giving me a really hard time. Only once I've been able to connect to the network (running WPA-PSK, no difference with WEP). When I closed the connection I was unable to get it up'n'running again and I've tried a million times. Have installed ndiswrapper running HP drivers for the wireless. Only if I remove to encryption I'm able to connect.

So, I took the computer to work where we have a lab with some other wireless access points and I was surprised when I had no difficulties connecting to Scientific Atlantas cable modem with wireless access point (EPC2434). I've connected a dozen times today and did the same a week ago with no problem.
When trying do to the same on a D-Link DI-524 I have the same problems as with Netgear, I'm prompted for the password but nothing happends. I can then switch back to SA with no problems at all. I can see loads of other APs but can only connect to the SA or the ones with no encryption.

I contacted NETGEAR support to ask them if they had any good ideas, the answer I got was that, sorry, we don't officially support Linux Ubuntu so we won't help you.

My quess is that the issue is connected to Ubuntu and Hardy and the support for different wireless chipset.

rgds
Milo

Hangdog42 07-31-2008 12:01 PM

For all you Ubuntu Hardy users out there, there is a bug in NetworkManager that is causing all sorts of problems when trying to connect to a WPA encrypted network. It works fine for non-encrypted or WEP encrypted networks, but not WPA. I recently installed Hardy on a friends laptop and ran into this. My solution was to uninstall NetworkManager and install Wicd, which immediately solved the problem.

kwesadilo 08-01-2008 09:14 PM

jolphil, thanks for all of your help. In the short term, I probably won't be getting a new router. Mine only has one antenna, whereas most b/g routers have two. Would this cause my transmit power to be weak?

Hangdog42, I tried installing Wicd, but it wouldn't connect to my wireless network. I tried putting quotes around the passphrase and putting it in in hex form like the FAQ said, but it still didn't work. I didn't test extensively, so I'll give it another shot later. With Wicd, I still saw the weird "default" and "KOZS7" networks. Maybe they're real, but I haven't seen them on any other computers. It's kind of weird. Thanks for the advice.

aws0 08-02-2008 07:16 AM

still no progress
 
Hangdog42, thanks for the tip.
I've installed Wicd but have still the same issue. When trying to connect to my AP using WPA the program freezes and I have to either reboot computer or restart gui. Turning off the encryption on AP I'm able to connect so the problem is still here.

Milo

jolphil 08-02-2008 07:43 AM

Quote:

Mine only has one antenna, whereas most b/g routers have two. Would this cause my transmit power to be weak?
No not really..Mine has only one antenna..The output of any b/g router has to meet FCC and other specifications and the output RF is mainly determined by the routers output stage not the antenna itself..A Badly matched or damaged antenna though can cause a serious loss in radiated power..If you look online at router specifications, you will see that most routers have an RF output of around 18dbm and that translates to around 64 milliwatts of power..The reading you got on your iwconfig test showed 8dbm output.That translates to around 6.4 milliwatts of RF energy..One tenth of what should be..Either a software issue is reading an incorrectly, or infact you really have a low output..
That Is why I would suggest using a live Linux CD and repeating the test..It would rule out a software issue..You can also take your laptop to another router(maybe a friends home) and connect, repeat the same test to help you determine what is wrong.If you get a strong reading on another router (somewhere around 15-20dbm)then it points to your home router as a problem. At this point There are just possibilities that you will have to work out..
Goodluck,
jolphil

Hangdog42 08-02-2008 08:03 AM

Quote:

Originally Posted by aws0 (Post 3234211)
Hangdog42, thanks for the tip.
I've installed Wicd but have still the same issue. When trying to connect to my AP using WPA the program freezes and I have to either reboot computer or restart gui. Turning off the encryption on AP I'm able to connect so the problem is still here.

Milo

Have you had a look in your log files to see if anything is leaving a clue? You also might try removing and re-installing (or even upgrading) wpa_supplicant. I believe most networking programs use it to deal with WPA encryption and it could be the install got hosed up.

aws0 08-03-2008 05:51 AM

Quote:

Originally Posted by Hangdog42 (Post 3234246)
Have you had a look in your log files to see if anything is leaving a clue? You also might try removing and re-installing (or even upgrading) wpa_supplicant. I believe most networking programs use it to deal with WPA encryption and it could be the install got hosed up.

Hangdog42, thanks again for answer regarding this. I've search loads of forums for good tips and answers for why this occurs. I've updated the wpasupplicant-files with no difference. The computer I bought seems to have issues running different linux-dists. Being a quite a newbie (a year or so) at linux makes the life a little harder but more interesting :p.

I could really need some good terminal command tips(or separate programs) to do a more correct investigation of the hand-over between access-point and computer. Only one I've used is dhclient giving me not so much more.

I still have to refer to my first comment where I found out that my cable modem with built-in wireless AP from Scientific Atlanta is working without any problems at all (running WPA-PSK) and this is what makes my brain to melt. WHY?
I could cope with a non-working wireless card at the computer due to lack of compability or else but what does SA-s equipment that the others don't?

Rrds
Milo

kwesadilo 08-05-2008 06:53 PM

Tx-Power with other distros
 
I put in a LiveCD of PCLinuxOS, and it connected to the network easily after I added my interfaces. Here's my iwconfig output.
Code:

IEEE 802.11g  ESSID:"*****"  Nickname:"******"
Mode:Managed  Frequency:2.437 GHz  Access Point: ******
Bit Rate:11 Mb/s  Tx-Power:17 dBm  Sensitivity=1/1
Retry:off  RTS thr:off  Fragment thr:off
Encryption key:*********  Security mode:restricted
Power Management:off
Link Quality=21/70  Signal level=-76 dBm  Noise level=-97 dBm
Rx invalid nwid:733  Rx invalid crypt:0  Rx invalid frag:0
Tx excessive retries:0  Invalid misc:0  Missed beacon:0

Update: I tried Knoppix, and I couldn't get WPA to work because it was missing some piece of software. I didn't investigate it very much. I was able to see the network, and I got 8 dBm Tx-Power when I ran iwconfig.

What do you think is causing this error?

jolphil 08-06-2008 07:04 AM

Now you know that it is some sort of a software issue that Hangdog42 mentioned..Your choices as I see it are to dig in the network configuration until you get it or to change distros..Your call..
Goodluck,
jolphil:twocents:

Edit: BTW your bit rate is still a little low as I see it.

Edit again: I was reading the router operation manual and it looks as though you are in the 802.11b state rather than the 803.11g state..That would account for the 11mbit rate..You need to review your router configuration and make sure you choose the /g state..

kwesadilo 08-06-2008 02:43 PM

802.11b/g bitrate
 
I went into the router configuration, and it was set up to accept connections from b devices and g devices. I would have thought that this would still give g connections to g devices, but, as you well know, this router has disappointed me before. So I switched to only accepting g connections. After I rejoined the network, I was delighted that not only did my bitrate go up to the expected 54Mb/s, but my Tx-Power actually went up to 17 dBm. My jubilation was short lived, however, as my next iwconfig produced the usual 8 dBm. A few minutes later, the bitrate decreased to 24 Mb/s.

Perhaps the most unusual affect of the configuration change is that my iwconfig output switches between IEEE 802.11g and IEEE 802.11a. How is this possible? 802.11a is a whole different spectrum.

I think I might be getting closer to a distro change. Ubuntu is based off of Debian, so would Debian Lenny have the same issue? I recall having WiFi issues when I tried Lenny before, but I can't remember what exactly the problem was.

Can you recommend other connection management software besides network-manager and Wicd? Is there a convenient way for me to get the software that worked on PCLinuxOS without switching to KDE?

jolphil 08-07-2008 07:20 AM

Quote:

Can you recommend other connection management software besides network-manager and Wicd? Is there a convenient way for me to get the software that worked on PCLinuxOS without switching to KDE?
I'm not sure I understand that question..I thought PCLOS was KDE..It was most likely tweaked by Texstar and his group I guess..
Maybe Hangdog42 0r others can help you here..

The only other suggestion I can offer for your case is to get an external AP that plugs in to one the 4 IP ports in the back of your router..That way you you use the AP's software and not the optical routers..I picked one up for about 20$ from newegg that I am now using with my wired router..Plus I can turn it on and off by just unplugging it when I want to..You can set it to a different channel so as not to interfere with the optical router or just turn off your routers RF..
If you go that route and want more info,let me know..
BTW I must say I give you an A+ for tenacity..
jolphil


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