What to do if wifi can scan networks but can't connect?

Question

I'm a newbie in Linux environment. I have a really, REALLY, bad problem.

I installed on my Asus X53Sv Ubuntu 14.10 but I have a problem:

the wifi works because it can recognize available networks BUT it can't connect! After I click "connect" it try to connect but after a couple of seconds it disconnects and says: "Disconnected - you are now offline".

I have already read this topic: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1173759

But I don't understand very well what I have to do (because I have a different laptop) and I have no internet (the ethernet port doesn't work)!

I have the following setup:

• Ubuntu: 14.10
• Wifi: Atheros AR9285
• Kernel: 3.16,0-23-generic

Anyone could help me, please?

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@mchid OMG, really thanks! I solved with this command:

echo 'options ath9k nohwcrypt=1' | sudo tee -a /etc/modprobe.d/ath9k.conf

But before to mark your reply I hope you will help me to another problem.. During I tried a lot of attempts I touched something I shouldn't touch because now everytime I start the computer it says "System program detected"... What could it be?

Solution

Open a terminal and try running this command:

This command will create a file named ath9k.conf in the folder /etc/modprobe.d that will contain the line "options ath9k nohwcrypt=1".

echo 'options ath9k nohwcrypt=1' | sudo tee -a /etc/modprobe.d/ath9k.conf

Reboot and try connecting to the network again. Please post any errors or if this fails to work.

click here to visit the source

Another thing you can do is to click on your network icon on your panel. Then, click on edit connections. Click on and delete any and all networks listed. Sometimes you may have a bad network configuration screwing things up so it's best to start fresh.

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Also, you say you also do not have ethernet. Do you have ports 68 and 67 open? You need these ports open for DHCP to assign an IP to your laptop.

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Does your router allow you to set a static IP without using DHCP? If so, you can set a static IP by clicking on the network icon on your dash. Then, click "Edit connections"; click on the wireless network and then click "edit"; click on "ipv4 settings"; change "Mode" from "automatic" to "manual" and then click "add". Use tab to navigate from Address to Netmask and then to Gateway.

Hint: you can easily get these numbers by booting up a live session from the Ubuntu installation DVD or USB (if wifi works). Click on the network icon on your dash and then click "connection information". You can then get a pad and paper and write these down.

"Address" is the static IP for the laptop you would like to set (for example: 192.168.1.44).

"Netmask" is usually 255.255.255.0 but it may differ depending on your router settings.

"Gateway" is usually 192.168.1.1 but it may also differ depending on your router settings.

Finally, DNS should be set to either the same IP as your Gateway (here in this example it would be 192.168.1.1) or to the IPs of DNS servers separated by a comma. For example, google dns is = 8.8.4.4,8.8.8.8

Click "save". If you cannot click save, click "cancel" and try again.

Run the following command to restart network-manager:

sudo service network-manager restart

Comments

[Xen2050]

I've had that problem before with a usb network adapter that wasn't fully supported, would need an updated driver (which I couldn't find)

[mchid]

what type of internet connection did you use to install Ubuntu?

[Xen2050]

@mchid I don't remember, it was about 2 years ago, and I just used a different USB wifi adapter that worked. Newer kernels/Ubuntus probably supported it but didn't try. No adapters I found work as good as dd-wrt-like tomato on an old router, even now ~10 years after they were sold :-)

[mchid]

"System program problem detected" is apport. Apport reports application crashes to the Ubuntu devs to help them fix common issues. It is best to click submit to help the developers. After have clicked to submit the problems, you should clean out your crashlog to prevent the same messages popping up every time you start up. To clean out your crashlog, run the following commands: first make a directory to place a backup of the files mkdir ~/Documents/crash and then move the files to the backup directory sudo mv /var/crash/* ~/Documents/crash. You should nolonger see the message at you start.

[mchid]

The crashlogs will be moved to a directory named "crash" in your Documents folder. This blogpost explains a little bit about it. binarytides.com/ubuntu-fix-system-program-problem-error

[Davide Scanu]

Really, really thanks for this! I edited my question, could you read the new part please?

[mchid]

@DavideScanu sure

[mchid]

@DavideScanu the problem should be listed as a file in the folder "/var/crash". If you have already made a backup and moved the files they will be located in the folder named "crash" in "Documents". Use any text editor (gedit, nano, cat, vi, etc . . . ) to open or view the files.

[mchid]

@DavideScanu most likely, it's probably nothing to worry about as long as everything seems to work okay. Check your "system log" to see if there is anything serious in there. Other than that, it's probably nothing.