Troubleshooting

Since the introduction of NetworkManager, connections can be enabled and disabled from the NetworkManager icon in the System Notification Area.

[Important]

Before attempting any troubleshooting, ensure that the connection is enabled:

  1. Right click the NetworkManager icon in the notification area.

  2. Check Enable Networking.

  3. Check Enable Wireless.

Wired troubleshooting

If you have a network connection which is not working properly, you can use a few tools to help diagnose what the problem is.

Most of the tools in this section require use of the Terminal, which you can open by pressing ApplicationsAccessoriesTerminal.

Get information about the current connection

ifconfig is intended to allow you to change the settings of your network connections, but it can also be used to list information about the current connection.

  1. Press ApplicationsAccessoriesTerminal to open a Terminal

  2. Type ifconfig eth1 in the Terminal and press Enter, replacing eth1 with the name of your network interface if it is different.

    • inet addr gives the current IP address of the connection

    • HWaddr gives the MAC address of your network device

Check if a connection is working properly

A good way of checking if a connection is working properly is to ping another computer on the network or the Internet.

To check if you are connected to the Internet:

  1. Press ApplicationsSystemNetwork Tools

  2. Select the Ping tab

  3. Type ubuntu.com into the Network address box and then press Ping

  4. After a while, a graph should appear. Look at the number for Successful packets under Transmission Statistics

    • 100% successful packets - Your computer should have a good connection to the Internet

    • Less than 100% successful - Your computer probably has a poor connection to the Internet or a poor wireless signal

    • 0% successful packets - Your computer has a very bad connection, or is connected to an access point or router which is not connected to the Internet

If you get an error message which says The address 'ubuntu.com' cannot be found, then your computer is probably not connected to the Internet or cannot reach a DNS server.

Wireless troubleshooting

While not exhaustive, this section covers some common problems faced with wireless support.

There is much more information available from the Community Documentation.

[Note]

This troubleshooting guide is designed to be carried out in order. If you reach the end of a section and are not directed to another - then try the section called “Wireless” and should it fail begin at the start again.

Check that the device is on

  1. Many wireless network devices can be turned on or off. Check to see if there is a hardware switch, some devices can be switched off from Windows and may need to be turned back on from Windows.

  2. If it is turned on then see the section called “Check for device recognition”.

Check for device recognition

  1. Open a Terminal (ApplicationsAccessoriesTerminal) and type the command: sudo lshw -C network

You should see an output, along with the words "CLAIMED, UNCLAIMED, ENABLED or DISABLED"

  1. Claimed - this indicates a driver is loaded but not functioning, see the section called “Using Windows Wireless Drivers”

  2. Unclaimed - there is no driver loaded, see the section called “Using Windows Wireless Drivers”.

  3. Enabled - move on to If there is a driver listed then see the section called “Check for a connection to the router”.

  4. Disabled - see the section called “Check that the device is on”.

Using Windows Wireless Drivers

Xubuntu supports a system known as NDISWrapper. This allows you to use a Windows wireless device driver under Xubuntu.

  1. Obtain the Windows Driver for your system and locate the file that ends with .inf.

  2. Install the ndisgtk package.

  3. Open ndisgtk (ApplicationsSystemWindows Wireless Drivers).

  4. Select Install new driver.

  5. Choose the location of your Windows .inf file and click Install.

  6. Click OK.

Check for a connection to the router

  1. Open a Terminal (ApplicationsAccessoriesTerminal) and type the command: iwconfig.

  2. If the ESSID for our router is shown there may be a problem with ACPI support. Boot the kernel with the pci=noacpi option.

Check IP assignment

  1. Open a Terminal (ApplicationsAccessoriesTerminal) and type the command: ifconfig.

  2. If there is an IP address shown see the section called “Check DNS”.

  3. From the Terminal enter the command: sudo dhclient if_name where if_name is the connection listed earlier.

  4. If you receive a message that says bound to xxx.xxx.xxx.xxx then see the section called “Check DNS”

  5. If not then reboot the system.

Check DNS

  1. Open a Terminal (ApplicationsAccessoriesTerminal) and type the command: ping -c3 85.190.27.2.

  2. Now type the command: ping www.ubuntu.com. If you get a response from the both then see the section called “IPv6 Not Supported”.

  3. Type the command: cat /etc/resolv.conf. If there is no nameserver listed then contact your ISP and find out your primary and secondary domain name servers. Once you have this information see the section called “Wireless”.

IPv6 Not Supported

  1. IPv6 is supported by default in Xubuntu and can sometimes cause problems.

  2. To disable it, open a Terminal (ApplicationsAccessoriesTerminal) and type the command: gksudo gedit /etc/modprobe.d/aliases.

  3. Find the line alias net-pf-10 ipv6 and change it to read alias net-pf-10 off.

  4. Reboot Xubuntu.