Ethernet stops working when computer sleeps

[brhad56]

Whenever my computer goes into sleep mode, my wired internet connection drops and will not start back up again. Very annoying. When I wake the computer back up, I cannot get the network connection back. I have tried restarting network-manager service to no avail. But even if it were to work, that would not be acceptable as the internet connection should not drop at all. This causes downloads to fail, etc. The only way I can get it back on is if I reboot. This problem started after I installed from scratch Kubuntu 11.10. I have used the past distributions on the same hardware without issue. When I boot into Windows 7, I do not experience this outage. I am using the on-board NIC from my ASUS M3A78 motherboard.

I am not sure what all diagnostic tests I need to run, but will be happy to provided if you can show me what to run.

[lo_koraco]

Is it a stationary computer or a laptop?

[brhad56]

Desktop

[SteveRiley]

Before your computer sleeps, note the output of this command:

ls -l /run/network

Once you resume the computer from sleep, try it again. Do the outputs differ?

[perspectoff]

Yeah, that was a pain for me, too. I didn't need Network-Manager so I uninstalled it (sudo apt-get remove network-manager-kde --purge). No more problems.

I manage the Ethernet connection "the old-fashioned" way using the configuration files (/etc/network/interfaces and /etc/resolv.conf, primarily). Since I only use a wired connection, this works well.

For my laptops I use Wicd, which works for me better than Network-Manager-kde (still).

[brhad56]

They look the same to me


Before it sleeps:

brad@Tempest:~$ ls -al /run/network
total 4
drwxr-xr-x  3 root root 120 2012-02-16 22:23 .
drwxr-xr-x 21 root root 780 2012-02-16 22:23 ..
-rw-r--r--  1 root root   6 2012-02-16 22:23 ifstate
-rw-r--r--  1 root root   0 2012-02-16 22:23 ifup.eth0
-rw-r--r--  1 root root   0 2012-02-16 22:23 ifup.lo
drwxr-xr-x  2 root root  40 2012-02-16 22:23 static-network-up-emitted
brad@Tempest:~$

After it sleeps:

brad@Tempest:~$ ls -al /run/network
total 4
drwxr-xr-x  3 root root 120 2012-02-16 18:25 .
drwxr-xr-x 21 root root 840 2012-02-16 18:45 ..
-rw-r--r--  1 root root   6 2012-02-16 18:25 ifstate
-rw-r--r--  1 root root   0 2012-02-16 18:25 ifup.eth0
-rw-r--r--  1 root root   0 2012-02-16 18:25 ifup.lo
drwxr-xr-x  2 root root  40 2012-02-16 18:25 static-network-up-emitted
brad@Tempest:~$

[SteveRiley]

Hm, OK, so my first thought flies out the window. Diagnosing network connectivity problems can sometimes involve several steps. What's the output of:

cat /etc/network/interfaces

[brhad56]

It's working now. I have a wireless card in the machine and it might have been confusing things, so from the network manager applet, i unchecked the "enable wireless" box. Thanks for helping trying to diagnose!