Ubuntu – Ethernet connection not working after installing Ubuntu 14.04 LTS


I cant figure out a permanent and reliable way around the bug (have managed the bug to go away 2 times) my files keep duplicating themselves with a ~ after their name, so if I modify rc.local, a file named rc.local~ pops out of nowhere, I dont understand what this does.

Also I dont have a /etc/init/module-init-tools.conf file, Im modifying the script in kmod.conf…

Help is appreciated.

EDIT: Problem solved thanks to https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1003297

I installed Ubuntu 14.04 LTS alongside Windows 7, my ethernet connection works without problem in Windows but it doesn’t work in Ubuntu. I think the problem is related to drivers and doesn’t allow me to aquire/assign an ip adress. Thank you for trying to help, Ill describe the problem ahead.

My wifi connection does work without problems.
When I desable my wifi: my network manager tries to connect using the wired connection 1 and it always returns "Disconnected – you are now offline", and then it tries to connect again and the cycle repeats (Disconnected – yo are now offline).

Diagnosis info:

~$ lspci | grep Ethernet

00:07.0 Bridge: NVIDIA Corporation MCP61
Ethernet (rev a2)

~$ ifconfig

Link encap:Ethernet HWaddr bc:5f:f4:6f:26:c0
inet6 addr: fe80::be5f:f4ff:fe6f:26c0/64 Scope:Link
RX packets:0 errors:12 dropped:0 overruns:11 frame:1
TX packets:140 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:27262 (27.2 KB)

Link encap:Local Loopback
inet addr: Mask:
inet6 addr: ::1/128 Scope:Host
RX packets:1679 errors:0 dropped:0 overruns:0 frame:0
TX packets:1679 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:147779 (147.7 KB) TX bytes:147779 (147.7 KB)

About my ethernet controller: I dont understand much but here is the info I got:

~$ sudo lshw -class bridge

description: Ethernet interface
product: MCP61 Ethernet
vendor: NVIDIA Corporation
physical id: 7
bus info: pci@0000:00:07.0
logical name: eth0
version: a2
serial: bc:5f:f4:6f:26:c0
size: 100000000
capacity: 100000000
width: 32 bits
clock: 66MHz
capabilities: bridge pm msi ht bus_master cap_list ethernet physical mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation
configuration: autonegotiation=on broadcast=yes driver=forcedeth driverversion=0.64 duplex=full latency=0 link=yes
maxlatency=20 mingnt=1 multicast=yes port=MII speed=100Mbit/s
resources: irq:44 memory:eeefd000-eeefdfff ioport:d080(size=8)

Finally I managed to get a script that diagnoses your connections, here is the output when my wifi is off and Im trying to connect trough my ethernet:

WARN: This system does not have a default route

INFO: Host localhost answers to ICMP pings

INFO: Loopback interface is working properly

INFO: The lo interface is up

INFO: The lo interface has IP address ::1/128 assigned

INFO: The lo interface has tx and rx packets.

INFO: The eth0 interface is up
INFO: The eth0 interface has IP address fe80::be5f:f4ff:fe6f:26c0/64 assigned
ERR: The eth0 interface has not tx or rx any packets. Link down?

WARN: The eth0 interface has rx errors.

WARN: The wlan0 interface is down

ERR: The system does not have any nameserver configured

WARN: System does not seem to reach Internet host www.debian.org through ICMP
WARN: Cannot access web server at Internet host www.debian.org

Thanks for reading and if you can help me out it will be greatly appreciated.

EDIT: $sudo lshw -class network

  *-network DISABLED      
   description: Wireless interface
   physical id: 1
   bus info: usb@1:4
   logical name: wlan0
   serial: 00:e0:4c:c0:c4:2c
   capabilities: ethernet physical wireless
   configuration: broadcast=yes driver=rtl8192cu driverversion=3.16.0-34-generic firmware=N/A link=no multicast=yes wireless=IEEE 802.11bgn

lsb_release -a

No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 14.04.2 LTS
Release:    14.04
Codename:   trusty

Best Answer

Note: I'm posting this workaround as an answer due to the number of times this has been reported as a bug only to expire shortly thereafter and resurface again.


  1. Enter Ubuntu recovery mode: a. Power on system and press Shift during boot up for GRUB menu.

    b. Choose "Advanced options for Ubuntu" > Ubuntu, [kernel version] (recovery mode)

  2. Choose "root" and key in below commands:

    rmmod forcedeth
    modprobe forcedeth msi=0 msix=0
  3. Choose "resume" to resume normal boot

Now the network should be OK till next boot with AM3+ CPU.

If the workaround works on your system, please modify below file to automatically run the script when boot up:

Bug Workaround Solution:

  1. Add the line exec rmmod forcedeth at next line of "script" (above grep?) in the file /etc/init/module-init-tools.conf or /etc/init/kmod.conf)

  2. Add the line modprobe forcedeth msi=0 msix=0 to /etc/rc.local

  3. Restart the system to verify

Sources: Primarily Achkap post #16 http://ubuntuforums.org/showthread.php?t=2020571&page=2




Clue from Julian Uribe in comments.

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