Wired internet connection doesn't work after Kubuntu 11.10 upgrade

Asked by Vojko Jazbinsek

After the Kubuntu 11.10 there is no wired (LAN) internet connection.

Before the upgrade everythig worked fine.

In the system settings I opened Internet connection, but I don't know what to do.

I have the folowing options:

Obtain an IP address automatically
Obtain DNS server automatically.

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Solved by:
Vojko Jazbinsek
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actionparsnip (andrew-woodhead666) said :

Can you give the output of:

sudo lshw -C network; lsb_release -a; uname -a


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Vojko Jazbinsek (vojko-jazbinsek) said :

Hera are the requeasted outputs:
sudo lshw -C network
 *-network DISABLED
       description: Ethernet interface
       product: RTL8111/8168B PCI Express Gigabit Ethernet controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:01:00.0
       logical name: eth0
       version: 03
       serial: 6c:62:6d:69:65:0b
       size: 100Mbit/s
       capacity: 1Gbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix vpd bus_master cap_list rom ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full latency=0 link=yes multicast=yes port=MII speed=100Mbit/s
       resources: irq:42 ioport:d800(size=256) memory:fbeff000-fbefffff memory:faffc000-faffffff memory:fbec0000-fbedffff

sudo lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 11.10
Release: 11.10
Codename: oneiric

sudo uname -a
Linux IMFM2857 2.6.35-22-generic-pae #35-Ubuntu SMP Sat Oct 16 22:16:51 UTC 2010 i686 i686 i386 GNU/Linux

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actionparsnip (andrew-woodhead666) said :

Do you have a switch to enable / disable the connection. If so, press it

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Benjamin Geiser (bgeiser8) said :

Could you please post the output of the following:

ls /etc/modprobe.d

Thank you.

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Vojko Jazbinsek (vojko-jazbinsek) said :

Thanks a lot for suggestions. I've solved the problem in the following way:
First, I typed the following command
    sudo ifup eth0
and I got the answer:
    Ignoring unknown interface eth0=eth0

Then I asked the google, how to configure eth0 in Kubuntu and I followed instruction I found in

I edit the file /etc/network/interfaces:
# The primary network interface - use DHCP to find our address
auto eth0
iface eth0 inet dhcp

Then I restart networking services using the following command
sudo /etc/init.d/networking restart

Network is now working without a problem.
However, I am a bit disappointing that I have to correct the file /etc/network/interfaces manually after upgrading to a new version of Kubuntu.
Note, that after upgrading, the /etc/network/interface file contained the following lines:
auto lo
iface lo inet loopback