Not all Wifi access points listed
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Hi!
I have a strange issue with a laptop my parents just got for gravmass: it does not list all Wifi access points. In fact it lists the neighbors' access points but not their own!
I naturally installed Trisquel 7 on that machine. The USB adapter they use is http://www.tp-link.us/products/details/?categoryid=243&model=TL-WN722N
I unsuccessfully tried to connect to the access point as if it was hidden. With the *same* adapter but on my own laptop (with Trisquel 7 too), the access point is properly listed and I can connect to it. Here are some information from iwlist's scanning:
Frequency:2.467 GHz (Channel 12)
Quality=37/70 Signal level=-73 dBm
Encryption key:on
ESSID:"maison"
Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 9 Mb/s
18 Mb/s; 36 Mb/s; 54 Mb/s
Bit Rates:6 Mb/s; 12 Mb/s; 24 Mb/s; 48 Mb/s
Mode:Master
Extra:tsf=00000008d6177ad1
Extra: Last beacon: 82044ms ago
IE: Unknown: 00066D6169736F6E
IE: Unknown: 010882848B961224486C
IE: Unknown: 03010C
IE: Unknown: 2A0104
IE: Unknown: 32040C183060
IE: Unknown: 2D1A6E1017FFFF000001000000000000000000000000000000000000
IE: Unknown: 3D160C070400000000000000000000000000000000000000
IE: Unknown: 3E0100
IE: WPA Version 1
Group Cipher : TKIP
Pairwise Ciphers (2) : TKIP CCMP
Authentication Suites (1) : PSK
IE: Unknown: DD180050F2020101000003A4000027A4000042435E0062322F00
IE: Unknown: 7F0101
IE: Unknown: DD07000C4300000000
IE: Unknown: DD1E00904C336E1017FFFF000001000000000000000000000000000000000000
IE: Unknown: DD1A00904C340C070400000000000000000000000000000000000000
I am running out of (stupid) idea. Anybody with a new one?
I am a translator!
hi magic! Did you try wicd?
also try to compare the wireless access points that work with those that don't work and maybe figure out what could be the issue..
I was not clear: the iwlist's scanning result comes from the working system. On the non-working system, iwlist only lists the neighbors' access points. Since iwlist has nothing to do with Network-Manager, Wicd would not do better.
I took your advice of paying a closer look at the properties of the access points listed on both system by iwlist. On the working one, there were three access points on the channel 12, including the one I want to connect to. On the non-working system, the scan did not return any of those access points. I therefore decided to reconfigure the Wifi router so that it uses the channel 4 (used by nobody in the neighborhood). After its restart, it works!
It makes no sense to me that the same Wifi adapter would detect access points on channel 12 when plugged in a laptop but not when plugged in another one. If anybody could provide an explanation, it would help me stay Cartesian! Happy gravmass and thank you!
Here's a few stupid ideas for you to try
* another USB port
* increasing the transmitter power on the router
Plugging the adapter in another USB port was one of my first unsuccessful try. I do not know how to increase "the transmitter power on the router". In fact, I do not even know what it means! :-)
Anyway, as written above, changing the channel and restarting the Wifi router did the trick... for some reason!
Glad it started working for whatever reason! (Don't you just hate it though when something suddenly works with no explanation!)
The wireless router (access point) is a radio and most routers allow you to control how much power they use to transmit. This is done via some control panel interface, e.g. at http://192.168.1.1. More power means more range (but not more throughput). It would be best if people used as little transmission power as possible for a number of reasons including conserving energy and not disturbing their neighbors with their signal.
Just to exclude a rather unlikely idea: you tried to connect with both laptops from the exact same spot, right?
It happens right next to the rooter, too?
I tried to connect in the same room as the router's and in another room, ~20 meters away. I tried to shutdown the other computers (believing in some kind of interference). That did not change anything.
As written above, changing the channel and restarting the Wifi router did the trick. If you have some kind of explanation, I would like to read it! :-)
Well, i don't have an explanation, but I see that the signal of channel 12 doesn't get processed on one of two laptops with identical software-setups and wifi device;
the only conclusion is that the signal gets lost because of some hardware element.
I'm not familiar with wifi that much; maybe somebody knows how the signal gets processed in detail and which hardware components can interfere.
I saw this:
Extra: Last beacon: 82044ms ago
I think this is unusually high, but might be just that the access point is set up that way.
You didn't receive a beacon frame for 82 seconds. That means that sometimes you might have to wait that much in order to detect the AP on the machine.
Increasing the signal might help, but your signal level isn't that low. You can have >11M speed with this level.
The result I gave was without 'sudo'. In this way, 'iwlist' immediately describes the access point the system is connected to, and only that access point. With 'sudo', 'iwlist' takes much more time and lists all access points. Also, the "last beacon" times always are much more recent. I therefore believe that only root can force a new scan of the available access points and the time is reset, hence far smaller (less than a second) when the results are returned.
Magic Banana said:
it does not list all Wifi access points. In fact it lists the neighbors' access points but not their own!
Assuming you had taken all security steps in your router. Your problem is not you computer, Why? because You can see your neighbors WIFI access point but Not yours
First thing:
I would try to ping the WAN, the router in your parents house.
example: ping 192.168.1.1 from your laptop for responsiveness.
If there is response, and still you can't access the router, telnet the router to check the DHCP settings{ routing tables and channel Bond they are using, channels between 1-15 and check transmit band 20 or 40 GHz B,N, OR G.
Most of the time is Automatic, but standard router in automatic has a failure, because the nearby spectrum of WIFI networks could be saturated by other routers signal. {Like if everyone hugging the same Band}. The channels 1-10 is normal channeling 11-15 is different region of the world. You have to work it and find out the best channel.
If it is auto or manual. Just save any setting and do an Internal software reboot,(soft reboot) not hardware because you will lose all the changes you have done. It will take the router to default settings.
I will recommend to do soft reboot before a hard reboot and change the channels. 99.8 will refresh the IP tables and work fine after that.
If that is giving issues as an access point, move the router around.
Considering environmental variables that will cause conflict. Any electric appliance nearby, less than three feet will cause transmit and receive noise and distortion.( Harmonic distortion)
Another issue is physical distortion, such as cement walls, brick walls, false walls interrupting the range. Most routers will work fine on the "N" band. Your antennas will do the job, normally is 3 to 5 db depending on the router.
Basically you will have to the leg work. I could go in full technical details but that will take a 350 pages of information. Anyhow congratulations, you have been introduced to world of routers by desperation.
Good Job in fixing your issue.
As I already wrote: the issue was (magically?) fixed by changing the channel (from 12 to 4) and restarting the router.
Why the same adpater was working on one Trisquel 7 laptop but not on the other one remains mysterious...
Have you checked if both laptops have the same regulatory domain
configured? Channels 12, 13 and 14 are available only in some
countries.
I am a member!
I think this is the likely right answer. I don't know how to check the regulatory domain that Michal Maslowski talks about. Magic Banana, you could, however, check what channels are available for each area or country where the computers were bought here.[0]
[0]https://en.wikipedia.org/wiki/List_of_WLAN_channels
Not all residential gateways (mostly inaccurately known as “routers”) bind themselves to the IP address to 192.168.1.1 (I know you said this is an example). The actual IP address for typical connections can be obtained by using “route” or “ip” and is listed under column “Gateway”. Not all residential gateways accept telnet connections; none in my experience does. The routing table of the router has nothing to do with this problem; it's a link layer problem as he doesn't even sees the network listed. It's not true that “Any electric appliance nearby, less than three feet will cause transmit and receive noise and distortion.”. The 3 ft figure is completely arbitrary. Almost none would generate actual distortion, though *some* will generate noise within the relevant band. Distortion is not the same as noise, distortion is a non-linear phenomenon (For instance, clipping is distortion) and none of the materials “such as cement walls, brick walls, false walls interrupting the range.” are non-linear, do they don't generate any measurable distortion (Though they do *attenuate*, *reflect* and *refract* the signal, which degrades it); even the lead section on the article of Wikipedia on "distortion" explains this. jodiendo: Your intend to help is good, thanks for visiting this forum and helping in what you can, but please stop spreading inaccurate knowledge and pretending you know the topic in depth “I could go in full technical details but that will take a 350 pages of information.” given that you lack an understanding of the basics (distortion, harmonics, suggesting to telnet to a residential gateway, etc.).
Regards.
marioxcc
I forgot some people are more guru than others. Thanks for your fantastic explanation.
Matter fact, I'll challenge you to find the 350 pages of information?
In case you forget, It is the routers manual that will explain in detail everything in step, in case you did not have one.
Including the basic steps. I own ASUS AC router, Ubiquity and Cisco/links routers, when I downloaded the manual of one of them, it was 350 pages. Your assertion it is very wrong.
What makes you think this matter?
You said:
Not all residential gateways (mostly inaccurately known as “routers”) bind themselves to the IP address to 192.168.1.1
My answer to you/
By factory default to access, most WIFI routers, the setting of 192.168.1.1 is bound-able in the wan gateway. Depending on the brand of router you are buying that IP could change. The DHCP is tie up to it.
That is why, most of the savviest will recommend to change to something else to avoid data conflicts with your ISP router , that is If your are dynamic IP. Static IP is different, but basic in the same story.
Again you are wrong.
You said:
“Any electric appliance nearby, less than three feet will cause transmit and receive noise and distortion.”. The 3 ft figure is completely arbitrary. Almost none would generate actual distortion, though *some* will generate noise within the relevant band. Distortion is not the same as noise, distortion is a non-linear phenomenon (For instance, clipping is distortion) and none of the materials “such as cement walls, brick walls, false walls interrupting the range.” are non-linear, do they don't generate any measurable distortion (Though they do *attenuate*, *reflect* and *refract* the signal, which degrades it);
Really?
That depends on the antenna size and amplifiers, Explain to me: Why the routers manufacture do not recommend to be near other electric appliances. including the more savviest on WIFI will tell you not to do it. Keep your distance. I think you forgot to read one of the Warning labels.
WIFI Degradation is the result of ANY KIND OF interruption. Either man made or Natural.
Again you are wrong/
marioxcc
I believe You never had an explanation, you just made your own sound Intelligent, but not to my eyes. I could sit here and pick in your comments all night, I won't, you are not my WIFI guru! neither I. You are just mad because at least I help out first. Sorry Mr. Not so savvy!
One more thing, Is not clipping You might be wrong in the matter. We are not sound recording in that matter.
Is all about inter-modulation distortion.
https://en.wikipedia.org/wiki/Intermodulation
Still, we did not gave Magic banana the full explanation that he wanted, he got partial.
Magic banana question was: Why the same adapter was working on one Trisquel 7 laptop but not on the other one remains mysterious...
So too end my comment:
WE FAIL HIM miserably!
At least I got 2 good suggestions right,
to change the channel and restart the router.
About you?
You got 3 wrong, \\\\You fail Mr. Guru////
I am a translator!
yep. some routers have this issue with the channels.. Now I remembered I had it on dlink some years ago!
glad you solved the issue magic
cheers
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