Knowledge Base

How to troubleshoot Wireless network issues in Ubuntu Linux on your Dell PC



The following article provides information on how to identify and resolve a wireless network issue on your Dell PC with Ubuntu Linux installed.


Table of Contents:

  1. Troubleshooting a Wireless Network Issue
  2. Identifying any issues outside the system
  3. Troubleshooting the Hardware
  4. Troubleshooting the Software
  5. Resolution

1. Troubleshooting a Wireless Network Issue

This guide is to take you through a troubleshooting guide for wireless network Wi-Fi issues. It is specifically geared to the Ubuntu Linux Operating System OS.

  1. Are you having wireless connection issues with a Dell PC?

    1. If it has a Windows Operating System installed then please go to the guide linked below:

    2. If it has Ubuntu installed please continue.


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2. Identifying any issues outside the system

  1. Can your system pick up any local Wi-Fi networks, but can't connect to them?

    1. It can see networks and connect to any other network but yours. You will need to contact your Internet Service Provider ISP. It looks like the network itself or your connection settings are at fault.

    2. It can see networks, but can't connect to any and Wi-Fi strength is low. Please proceed with step 2.

    3. It can't see any networks even when held over the router. Please proceed with step 2.

    4. It can intermittently see and connect to available wireless networks. Please proceed to section 3, step 1.

    5. It doesn't see you have a Wi-Fi card installed. Please proceed to step 3.

  2. Can other devices connect to the Wi-Fi ok?

    1. If they can, carry on with the guide.

    2. If not, again you will want to see your ISP about a general network issue.

  3. If you boot the system to the Basic Input Output Setup BIOS can you see the Wi-Fi card as installed correctly and that it's detected?

    1. If its detected then proceed with the guide.

    2. If it's not detected proceed to section 3 step 1.

Note: Press the <F2> key at the Dell splash screen and navigate to the onboard devices.

  1. In the BIOS check that the wireless is enabled and disable the Wi-Fi switch if your system has one installed. Boot back to the OS and confirm if issue continues?

    1. It does, proceed with the guide.

    2. It doesn't, go back into the bios and re-enable the Wi-Fi switch. If the fault comes back contact your Technical Support to resolve this issue. If the fault doesn't come back your issue should be resolved.

    3. It doesn't have a switch, proceed to the next step.


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3. Troubleshooting the Hardware

  1. Boot from the Ubuntu Linux Media, either a CD or a USB and advise if issue occurs while in that OS?

    1. If it works fine, you're looking at a clean install and driver reinstall.

    2. If it is the same please proceed with this guide.

Note: Press the <F12> at the Dell splash screen and select either CD or USB boot from the options menu that appears. Then select Try Ubuntu to boot off of the media, instead of your Hard Drive.

  1. The best way to rule out a hardware issue is to two way swap the Wi-Fi card with another compatible system.

    1. You were able to swap out the Wi-Fi card and :

      1. The fault followed the original card to the working system and the card from the working system works in the your machine. Contact your technical support to have the hardware issue resolved.

      2. The fault stayed with the working card in your system and your card is working fine in the working machine. Continue with this guide.

      3. The fault goes away on both machines. It was a loose connection and your issue should be resolved.

    2. If that isn't possible then reseat the Wi-Fi card and antenna cables :

      1. If the situation changes and the Wi-Fi starts working it was a loose connection and your issue should be resolved.

      2. If you're issue continues please proceed with the next step.

Note: You can find your system manual on our support site as long you have your tag or model type.


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4. Troubleshooting the Software

  1. Run the following troubleshooting steps on the wireless adapter:

    1. Open Terminal (CTRL+Alt+T)

    2. Get the details from the adapter using the following command:

      sudo lshw -class network
    3. You should get a result that looks something like this:

      product: Intel8720A Wireless Network Adapter
    4. Run the following commands:

      /etc/pm/config.d/config;

      and

      SUSPEND_MODULES="<adapter model>"
    5. Enter the following command:

      echo "options <adapter model> fwips=N" | sudo tee /etc/modprobe.d/rtl8723be.conf
    6. Reboot the system and check if the issue occurs again?

      1. Yes, the issue is resolved and everything is working fine now.

      2. No, the issue continues and is intermittent. Please contact technical support to troubleshoot this further.

      3. No, the issue continues and is constant. Please proceed to the next step.

  2. Scan for networks using NetworkManager. Click on the NetworkManager on your menu bar.

  1. The dropdown menu will show a list of wireless networks in range. Select from the list to connect.

    1. It sees the networks but won't connect to any. Proceed with next step.

    2. It doesn't see any networks. Contact your Technical support to resolve this issue.

  1. Scanning from the command line is another option. Click Dash Home > Search > Terminal. The Terminal program will launch.

  1. Enter the following comanad in terminal:

    iwconfig

  1. The system will display a list of network adaptors :

    eth0

    no wireless extensions

    lo

    no wireless extensions

    wlan0

    IEEE 802.11bgn ESSID:off/any mode: Managed Access Point: Not-Associated Tx-Power: 16dBm Sensitivity=0/3 Retry long limit: 7 RTS thr: off Fragment thr: off Power Management: off

    wlan0

    is the wireless adaptor entry

  2. Enter the following command in terminal: (Where <ethX> is the name of the wireless adaptor as found in the last command.)

    sudo iwlist <ethX> scan
  3. The system will scan for access points and return a list of the ones it has found. The output from the scan will contain some useful information. Look for these pieces of information that might help your troubleshooting.

    ESSID

    This is the wireless network name, SSID

    Mode

    This is the wireless network access mode, Managed=Access Point Mode

    Quality

    This number indicates the signal quality, from 1 - 5

    Encryption key

    This indicates if this network requires an encryption key.


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5. Resolution

  1. Do the results point to a hardware or software issue?

    1. If the Hardware is faulty contact your Technical Support with the troubleshooting you've done to get the issue resolved.

    2. If the hardware is verified to be working, but your issue persists, then the next step would be to get in touch with Canonical the suppliers of Ubuntu Linux and the built in drivers. They will be able to take you through in-depth software and driver troubleshooting to resolve your issue. You can find all of their information on the Ubuntu Community Support External Link page as well as a community support group that will also attempt to resolve any issues that remain.

If at any point what you see differs from what's described, please contact your technical support for further aid to resolve the problem.


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Additional Information :

Note:
Software support is provided by Canonical through the following methods:
Technical Support is provided by Dell :


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Article ID: SLN151759

Last Date Modified: 08/22/2017 04:44 AM


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