Lost Internet After Last Kernel Update

[delta-dude]

Machine is set up using a static IP address. Network interface is industry standard wired Ethernet (100 Mbit). I use no wireless devices. Panel/gutter showed Ethernet icon and status of connection. After update icon changed to the knetworkmanager icon and machine had no eth0 connectivity. Diagnostics so far include -

contents of etc/issue
Ubuntu 10.04 2 LTS \n \l
-----------

results from ifconfig command

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:88 errors:0 dropped:0 overruns:0 frame:0
TX packets:88 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:5280 (5.2 KB) TX bytes:5280 (5.2 KB)
-----------
resuts from ifconfig eth0

eth0: error fetching interface information: Device not found
-----------
resullts from

~$ ifconfig eth0 up
eth0: ERROR while getting interface flags: No such device
----------
Contents of etc/resolv.conf

# Generated by NetworkManager
domain xxxx-xxxx
nameserver 216.237.72.66
nameserver 216.237.77.2
nameserver 208.67.222.222
nameserver 208.67.220.220
-----------
Contents of etc/network/interfaces

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
address 192.168.0.119
netmask 255.255.255.0
network 192.168.0.0
broadcast 192.168.0.255
gateway 192.168.0.1
-----------
Result from - route -n

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
-----------
Results from uname -a

xxx-xxx xxxx-xxxx-desktop:~$ uname -a
Linux xxx-xxxx-desktop 2.6.32-33-generic #70-Ubuntu SMP Thu Jul 7 21:09:46 UTC 2011 i686 GNU/Linux
-----------
KDE Version
Platform Version 4.4.5 (KDE 4.4.5)
-----------
Results from sudo ifup eth0

SIOCSIFADDR: No such device
eth0: ERROR while getting interface flags: No such device
SIOCSIFNETMASK: No such device
SIOCSIFBRDADDR: No such device
eth0: ERROR while getting interface flags: No such device
eth0: ERROR while getting interface flags: No such device
Failed to bring up eth0.
-----------

Removing knetworkmanager did not help. Removing Virtual Box also did not help. It's like eth0 disappeared from the machine. I would prefer to have a simple way to manually configure a static Ethernet interface for the machine that is reliable and can not be removed.

Any ideas or guidance on how eth0 is setup under 10.04 would be a great help.

[Snowhog]

Just run ifconfig (without any options) in the console and check what it is reporting as interfaces.

[delta-dude]

The output for ifconfig alone is as follows -

ifconfig
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:88 errors:0 dropped:0 overruns:0 frame:0
TX packets:88 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:5280 (5.2 KB) TX bytes:5280 (5.2 KB)

I downloaded the latest Kubuntu 10.04 LTS .iso and cut a disk. I then booted the machine in "live" CD mode and I was able to configure network access manually. I never did get the dreaded knetworkmanage icon in the gutter/tray, only the cable icon. Guess what! The machine works perfectly. ifconfig reports everything correctly. My conclusion is the latest upgrade hosed my eth0 port big time.

In my view Kubuntu is a great operating system minus knetworkmanager and the new boot software. Does anyone know how to boot from a previous kernel upgrade? Dual boot and older configs listed the previous kernels and is was easy boot from one of those if an update hosed something.

Again, does anyone know how to set the machine up manually without using the knetworkmanager? Obviously the live CD does exactly what I want done. Any help in this area much appreciated.

[delta-dude]

Follow up. For anyone else fighting such a problem, let me add a couple of references. The first is from usr/share/doc/network-manager-README.Debian -

NetworkManager consists of two parts: one is on the system level daemon that
manages the connections and gathers information about new networks. The other
is a systray applet that users can use to interact with the NetworkManager
daemon.

Managed vs. Unmanaged mode and /etc/network/interfaces
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Devices listed in /etc/network/interfaces _will_ be managed by NetworkManager
unless the ifupdown system-config-setting is enabled and is setup to run
in "Unmanaged mode".

Note: in ubuntu/intrepid "Unmanaged mode" will be the default, but that is likely
to change in one of the following releases.

The config to select unmanaged/managed mode is in /etc/NetworkManager/nm-system-settings.conf:

[ifupdown]
managed=true/false

Unmanaged mode will make NetworkManager not touch any wired/wireless device matching
an interface name configured in /etc/network/interfaces.

and from etc/NetworkManager/nm-system-settings.conf

# This file is installed into /etc/NetworkManager, and is loaded by
# NetworkManager by default. To override, specify: '--config file'
# during NM startup. This can be done by appending to DAEMON_OPTS in
# the file:
#
# /etc/default/NetworkManager
#
#There is no /etc/default/NetworkManager - added

[main]
plugins=ifupdown,keyfile

[ifupdown]
managed=false

In spite of all this I still got hosed.