Ubuntu "wired network-device not managed"

Problem: After Ubuntu is upgraded, It is found in NetworkManager that only wireless network connections are allowed. The location of the wired eth0 shows "device not managed"

It should be that networlmanager does not manage wired connections.

Google to the solution, the specific principle is not very clear, just as prompted, can solve the problem, archive for future viewing

 

 

Ubuntu 9.04 "wired network-device not managed"

By Craig Mayhew on jun.13, 2009, under guides/fixes, Linux/Ubuntu

After upgrading to Ubuntu 9.04 I 've found the Network Manager GUI to be far superior to the previous version I was using in Ubuntu 8.04 lts. unfortunately when I was using Ubuntu 8.04 I made some M alterations to my network setup in the "/etc/Network/interfaces" file. the Network Manager in 9.04 wasn't keen on this and so refused to manage it, instead it displayed the message "wired network-device not managed ".

As a work around I commented out all of my changes by placing a # At the beginning of each line in my interfaces file:

Open the interfaces file in an Editor:

sudo vim /etc/network/interfaces

This is an example of how my file looked before I modified it. Yours will be different:

 

Auto Lo
Iface lo Inet loopback
Iface eth2 Inet static
Address 192.168.0.44
Netmask 255.255.255.0
Gateway 192.168.0.1
Auto eth2

 

And here's the same file again, but I 've added #'s at the beginning of each line so that they are ignored:

#auto lo#iface lo inet loopback#iface eth2 inet static#address 192.168.0.44#netmask 255.255.255.0#gateway 192.168.0.1#auto eth2

In order for the changes to take effect, 

we need to restart the network manager and the applet by running each of these in the command line:

sudo /etc/init.d/networking restar

And now restart the network manager applet:

 

Pkill nm-Applet
Nm-Applet

You shoshould now be able to manage the network connection from within the Network Manager applet.

 

Note: 1. For NM Management of Wired connections, you also need to edit the file/etc/NetworkManager/nm-system-settings.conf to put [ifupdown]
The managed = false option is set to true2.kill nm-after the applet is restarted, it does not work. After the NetworkManager process is killed, the modification takes effect.