rustybolt
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[Solved] Raspbian doesn't detect my wifi

Tue May 03, 2016 2:31 pm

I have Raspbian Jessie on a raspberry Pi 3 model B. I am unable to see my wifi network listed, even though I'm practically next to the router (on my laptop right next to it, the wifi shows up as the network with the best connectivity). Raspbian shows quite some wifi networks, even those from my neighbours, but my network is simply not there. When I do

Code: Select all

wpa_cli scan
sleep 5
wpa_cli scan_results
my wifi network is not there either (but all the others are). I tried to set the network directly in /etc/wpa-supplicant/wpa_supplicant.conf, but this did not help.

Another issue is that I can not log in on eduroam (this network does show up though). This is a wifi network for students, provided by the university (I live in student housing) that you need to log in to. When I click it, Raspbian says 'Failed to disconnect.' even though it is not connected to any other network.

So basically, I have two networks that I should be able to use, but I can use none of them. Any tips/help/recommendations would be greatly appreciated. I don't want to buy a router or use an ethernet cable.
Last edited by rustybolt on Sat May 14, 2016 1:31 pm, edited 1 time in total.

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MarkHaysHarris777
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Location: Rochester, MN

Re: Raspbian doesn't detect my wifi (it's next to the router

Tue May 03, 2016 3:15 pm

rustybolt wrote: So basically, I have two networks that I should be able to use, but I can not use [any] of them. Any tips/help/recommendations would be greatly appreciated.
A couple of things: 1) sometimes you can be too close to the wifi hotspot. Essentially, the hotspot overdrives the wifi receiver and no go... move the PI away from the hotspot 1.5 to 2.0 meters away and try again, 2) your hotspot may be configured to NOT broadcast the SSID. Some people think this gives them better security... its actually a PITA... make sure your hotspot is broadcasting.

Check with your student housing network people... sometimes the router|wifi_hotspot needs to be rebooted (seen this all the time). Make sure you understand their security protocols, passkeys, &c.

Frankly, and this is a sidebar, in student housing if you have an ethernet option, use it. You'll have a better connection, and it will be more secure.

marcus
marcus
:ugeek:

rustybolt
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Re: Raspbian doesn't detect my wifi (it's next to the router

Tue May 03, 2016 3:20 pm

MarkHaysHarris777 wrote:
rustybolt wrote: So basically, I have two networks that I should be able to use, but I can not use [any] of them. Any tips/help/recommendations would be greatly appreciated.
A couple of things: 1) sometimes you can be too close to the wifi hotspot. Essentially, the hotspot overdrives the wifi receiver and no go... move the PI away from the hotspot 1.5 to 2.0 meters away and try again, 2) your hotspot may be configured to NOT broadcast the SSID. Some people think this gives them better security... its actually a PITA... make sure your hotspot is broadcasting.

Check with your student housing network people... sometimes the router|wifi_hotspot needs to be rebooted (seen this all the time). Make sure you understand their security protocols, passkeys, &c.

Frankly, and this is a sidebar, in student housing if you have an ethernet option, use it. You'll have a better connection, and it will be more secure.

marcus
The router is a couple of meters away (it is in the next room), so this shouldn't be the problem. I can pick up the network without knowing the network ID beforehand on other devices, so I don't think this is the problem either. The eduroam network also works fine on other devices...

I do have an ethernet cable, but I want to use that for a server (that way I don't have to buy a router that is more expensive than the whole raspberry pi). I do use it now and it works perfectly, but when I do, my server is offline.

Thanks for the suggestions though :)

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MarkHaysHarris777
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Re: Raspbian doesn't detect my wifi (it's next to the router

Tue May 03, 2016 3:30 pm

rustybolt wrote: The router is a couple of meters away (it is in the next room), so this shouldn't be the problem.
ok..
rustybolt wrote: I can pick up the network without knowing the network ID beforehand on other devices, so I don't think this is the problem either.
If you 'see' other networks your receiver is working... if you don't see your network then the hotspot is NOT broadcasting... make sure you know what the SSID is; you don't have to see it to connect to it, but you do need to know the SSID...
rustybolt wrote:The eduroam network also works fine on other devices...
ok... again, check with the IT people and make sure you understand the protocols, passkeys, &c.
rustybolt wrote: I do have an ethernet cable, but I want to use that for a server (that way I don't have to buy a router that is more expensive than the whole raspberry pi). I do use it now and it works perfectly, but when I do, my server is offline.
You might consider putting your 'server' on your PI. My PI B+ is a nameserver, openvpn server, print server, and ssh server... just saying... on the other hand, if you want to get on the network with your pi, and the eth0 nic is the only thing you can get working, well, use it!
rustybolt wrote: Thanks for the suggestions though :)
Anytime.
marcus
:ugeek:

rustybolt
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Re: Raspbian doesn't detect my wifi (it's next to the router

Tue May 03, 2016 3:53 pm

MarkHaysHarris777 wrote: If you 'see' other networks your receiver is working... if you don't see your network then the hotspot is NOT broadcasting... make sure you know what the SSID is; you don't have to see it to connect to it, but you do need to know the SSID...
The hotspot IS broadcasting: I can see the network on all other devices I've tried. Or am I using a wrong definition of broadcasting here?
rustybolt wrote:The eduroam network also works fine on other devices...
ok... again, check with the IT people and make sure you understand the protocols, passkeys, &c.
Yeah, I didn't really answer this suggestion and I should have been clearer on this. I understand the protocols and settings but I don't know where to set these in Raspbian, and how to connect to it.
rustybolt wrote: I do have an ethernet cable, but I want to use that for a server (that way I don't have to buy a router that is more expensive than the whole raspberry pi). I do use it now and it works perfectly, but when I do, my server is offline.
You might consider putting your 'server' on your PI. My PI B+ is a nameserver, openvpn server, print server, and ssh server... just saying... on the other hand, if you want to get on the network with your pi, and the eth0 nic is the only thing you can get working, well, use it!
That is a good suggestion. The machine I use for the server has a lot more HDD memory and I use it mainly as an ftp fileserver, which is why I don't use the pi.
Last edited by rustybolt on Tue May 03, 2016 5:53 pm, edited 1 time in total.

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procount
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Re: Raspbian doesn't detect my wifi (it's next to the router

Tue May 03, 2016 4:04 pm

Do you know what channel your Wifi access point is broadcasting on?
Do you know what country your RPi wifi is configured to?

Depending on which country you are in, some channels are not valid, so if your Pi wifi is configured to a country that does not allow the channel that your wifi is broadcasting on, it will not see it, but it will see all the other networks that are on the other valid channels.
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MarkHaysHarris777
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Re: Raspbian doesn't detect my wifi (it's next to the router

Tue May 03, 2016 4:08 pm

procount wrote: ... so if your Pi wifi is configured to a country that does not allow the channel that your wifi is broadcasting on, it will not see it, but it will see all the other networks that are on the other valid channels.
I always forget that! ... um, we don't have that problem in the States.
marcus
:ugeek:

rustybolt
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Re: Raspbian doesn't detect my wifi (it's next to the router

Tue May 03, 2016 6:05 pm

procount wrote:Do you know what channel your Wifi access point is broadcasting on?
Do you know what country your RPi wifi is configured to?

Depending on which country you are in, some channels are not valid, so if your Pi wifi is configured to a country that does not allow the channel that your wifi is broadcasting on, it will not see it, but it will see all the other networks that are on the other valid channels.
This seemed very promising as the country was set to GB and I live in the Netherlands, but changing it to the Netherlands didn't change anything... (Suddenly Raspbian seems to be crashing a lot! I never noticed this before, but I had to do four reboots before I could set the wifi country without crashing...)

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DougieLawson
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Re: Raspbian doesn't detect my wifi (it's next to the router

Tue May 03, 2016 9:00 pm

MarkHaysHarris777 wrote:
procount wrote: ... so if your Pi wifi is configured to a country that does not allow the channel that your wifi is broadcasting on, it will not see it, but it will see all the other networks that are on the other valid channels.
I always forget that! ... um, we don't have that problem in the States.
Yes you do. The United States disallows channel 13, that's why my UK network sits on channel 4 because my HP printer won't connect on channel 13. It probably explains why channel 13 is very lightly loaded in my neighbourhood (channel 1 & 11 are full of access points).
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Cancelor
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Re: Raspbian doesn't detect my wifi (it's next to the router

Wed May 04, 2016 5:11 am

I guess there is a difference between seeing a broadcast SSID (on a list of possible SSIDs) and seeing the SSID used by a device that is already connected.

If you know the SSID you want to connect to then use

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sudo nano /etc/wpa_supplicant/wpa_supplicant.conf
to add it to the end of wpa_supplicant.conf so that it looks like this

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scan_ssid=1

network={
        ssid="abcdefgh"
        psk="xxxxxxxx"
        key_mgmt=WPA-PSK
}
make sure /etc/network/interfaces is as original - looks like this:-

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# interfaces(5) file used by ifup(8) and ifdown(8)

# Please note that this file is written to be used with dhcpcd
# For static IP, consult /etc/dhcpcd.conf and 'man dhcpcd.conf'

# Include files from /etc/network/interfaces.d:
source-directory /etc/network/interfaces.d


auto lo
iface lo inet loopback

iface eth0 inet manual

allow-hotplug wlan0
iface wlan0 inet manual
    wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

allow-hotplug wlan1
iface wlan1 inet manual
    wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
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rustybolt
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Re: Raspbian doesn't detect my wifi (it's next to the router

Fri May 13, 2016 11:38 am

Cancelor wrote:I guess there is a difference between seeing a broadcast SSID (on a list of possible SSIDs) and seeing the SSID used by a device that is already connected.

If you know the SSID you want to connect to then use

Code: Select all

sudo nano /etc/wpa_supplicant/wpa_supplicant.conf
to add it to the end of wpa_supplicant.conf so that it looks like this

Code: Select all

scan_ssid=1

network={
        ssid="abcdefgh"
        psk="xxxxxxxx"
        key_mgmt=WPA-PSK
}
make sure /etc/network/interfaces is as original - looks like this:-

Code: Select all

# interfaces(5) file used by ifup(8) and ifdown(8)

# Please note that this file is written to be used with dhcpcd
# For static IP, consult /etc/dhcpcd.conf and 'man dhcpcd.conf'

# Include files from /etc/network/interfaces.d:
source-directory /etc/network/interfaces.d


auto lo
iface lo inet loopback

iface eth0 inet manual

allow-hotplug wlan0
iface wlan0 inet manual
    wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

allow-hotplug wlan1
iface wlan1 inet manual
    wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
Thank, but I already tried this. Also, the wifi is broadcasting the SSID. Other devices that have never connected to it can find it.

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procount
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Re: Raspbian doesn't detect my wifi (it's next to the router

Fri May 13, 2016 11:56 am

What is the output of:

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iwlist channel
What channel is the SSID using?
You can use one of your other devices that does connect to it to display this information.

My RPi 3 only reports 11 channels, even though it is set to GB

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pi@raspberrypi:/ $ iwlist channel
wlan0     11 channels in total; available frequencies :
          Channel 01 : 2.412 GHz
          Channel 02 : 2.417 GHz
          Channel 03 : 2.422 GHz
          Channel 04 : 2.427 GHz
          Channel 05 : 2.432 GHz
          Channel 06 : 2.437 GHz
          Channel 07 : 2.442 GHz
          Channel 08 : 2.447 GHz
          Channel 09 : 2.452 GHz
          Channel 10 : 2.457 GHz
          Channel 11 : 2.462 GHz
The allowable channels in UK and NL are 1-13 See here

This penturalabs website suggests a solution to get the missing channels 12-13 back, but I haven't tried it.
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rustybolt
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Joined: Mon Apr 18, 2016 5:22 pm

Re: Raspbian doesn't detect my wifi (it's next to the router

Sat May 14, 2016 1:29 pm

procount wrote: What channel is the SSID using?
You can use one of your other devices that does connect to it to display this information.
Indeed, the wifi was on channel 12 and this channel was not scanned by the raspberry.
procount wrote: This penturalabs website suggests a solution to get the missing channels 12-13 back, but I haven't tried it.
Sadly, the link that points to the actual source code you have to compile 404's. Luckily, I have access to the router, so I just changed the channel to a lower one (which seems to be better anyway, regarding interference from other networks).

This is of course not solving the real problem, but it works (very well, actually) in this case: I'm posting this from my raspberry :)

Thank you! This saves me a lot of money/trouble!

Jack-Hammer
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Joined: Tue Jun 18, 2019 10:57 pm

Re: [Solved] Raspbian doesn't detect my wifi

Wed Jun 19, 2019 12:28 am

FWIW, I spent countless hours dealing with a similar problem that lead me to this posting. While my Pi could see all networks except my AT&T router, the solve in my case was to change the channel settings from auto to a specific channel (in my case, I randomly chose #8) on the 2.4 GHz network. Finally the Pi connected to the router.

Good luck to those that may experience a similar problem!

AshF
Posts: 1
Joined: Mon Jul 06, 2020 1:44 pm

Re: [Solved] Raspbian doesn't detect my wifi

Mon Jul 06, 2020 1:50 pm

Thank you very much for this post. I have to deal with this problem for the last few days whereby my Access Point was right next to my Pi 3B, however the Pi just did not see it. I was beginning to lose hope until I tried what Jack-Hammer suggested in the previous post to mine.... As soon as I changed the channel to 12.... it connected!

Thanks all and Jack-Hammer!

Ash

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