Internet on Ubuntu 12.04 LTS stopped to work after installing updates from the update manager

Can you ping 8.8.8.8?

Andrew, I did ping 8.8.8.8 and got "Network is unreachable"

I have an ethernet cable to conect to internet and I have the same problem:

Today I updated Ubuntu 12.04 then no internet.

my /etc/network/interfaces didn't change at all
and the network service is not compatible anymore with that version ...

If anyone solved that, thanks for help ...

I tried an ethernet cable to conect to internet and I had the same problem as when I try wireless. my /etc/network/interfaces didn't help as well... I also hope someone can solve it, I would be very thankful

ip add gives:

1: lo: LOOPBACK,UP,LOWER_UP mtu 16436 qdisk noqueue state UNKNOWN
link/loopback 00.00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo inet6 ::1/128 scope host valid_lft foreverpreferred_lft forever

2:eth0: BROADCAST,MULTICAST mtu 1500 qdisk noop state DOWN qlen 1000
link/ether f4:6d:04:81:89:23 brd ff:ff:ff:ff:ff:ff

3: wlan0: BROADCAST,MULTICAST mtu 1500 qdisk noop state DOWN qlen 1000
link/ether 48:5d:60:ad:1e:c6 brd ff:ff:ff:ff:ff:ff

ip route does not give anything

smod: command not found

/etc/network/interfaces: Permission denied

I found a solution:
edit this file
/etc/NetworkManager/NetworkManager.conf

change this
managed=false ===>>> managed=true

Then it works, I don't know why it was changed (if it has been changed) ...

If anyone has some idea about this :)

fayard, thanks, I did what you recommended, but unfortunately it did not help. Do you have some other idea what I can do?

/etc/network/interfaces: auto lo iface lo inet loopback auto eth0 iface eth0 dhcp

ip route: default dev wlan0 scope link metric 1003 169.254.0.0/16 dev wlan0 proto kernel scope link src 169.254.8.123

ip add result changed today in wlan: 3.wlan0 NO-CARRIER,BROADCAST,MULTICAST,UP mtu 1500 qdisk noop state DOWN qlen 1000 link/ether 48:5d:60:ad:1e:c6 brd ff:ff:ff:ff:ff:ff inet 169.254.8.123/16 brd 169.254.255.255 scope link wlan0:avahi

Ping 8.8.8.8 gave new result today: Ping 8.8.8.8 (8.8.8.8) 56(84) bytes of data. From 169.254.8.123 icmp_seq=1 Destination Host Unreachable

@Roman
Sorry, I have no more idea. It is still working fine at my place

The solution offered by drewski22785 on ask.ubuntu.com solved my problem:

I had the same issue, luckily I was able to figure out a fix. There appears to be an issue with the latest update of Network Manager. If you open the Ubuntu Software Center, go to History, search the keyword "Network" and you will probably see "network-manager (0.9.4.0-0ubuntu4, 0.9.4.0-0ubuntu4.1)".

If you see this then you have the same problem as I did. The solution is to downgrade to version 3: Search in Google "ubuntu network-manager package" and select the ubuntu.com link, then scroll down the page to "network-manager-dbg" select the precise (debug) ubuntu3 version.

http://packages.ubuntu.com/precise/network-manager-dbg

Download the 4 related packages for your system (amd64 or i386):

network-manager (= 0.9.4.0-0ubuntu3)
network management framework (daemon and userspace tools)

libnm-util2 (= 0.9.4.0-0ubuntu3)
network management framework (shared library)

libnm-glib4 (= 0.9.4.0-0ubuntu3)
network management framework (GLib shared library)

libnm-glib-vpn1 (= 0.9.4.0-0ubuntu3)
network management framework (GLib VPN shared library)

Install each of them using the command sudo dpkg -i FILENAME.

Restart your computer and that should fix your problem!

Thanks to everyone who gave advices!

Or install wicd (if you don't use 3G)

Last time I upgraded last summer and entered this problem, now I just made the upgrade again and had the same error. So the problem still exists?
Is it supposed to always downgrade network tools after upgrading, in LTS version? Happily I have another computer so I can download the packages.
Can these packages be marked so that they are not upgraded automatically?