Ubuntu Network Manager

Fix networking when installed from NFS/Live CD to use network manager

remove this entry from "/etc/network/interfaces" which will have been created and stop network manager working, cursor down, ctrl-k deletes line, ctrl-o save

sudo nano -w /etc/network/interfaces

#remove these two lines and save
auto eth0
iface eth0 inet manual

#restart network manager, should pick up and perform dhcp
sudo service network-manager restart

If you network card isnt eth0, fix this here

sudo nano -w /etc/udev/rules.d/70-presistent-net.rules
# remove everything from below the # comment block bit, save reboot.

To see current network manager settings

nm-tool

Current connections

nmcli con

To add additional DNS servers in Ubuntu 12.04 , using dnsmasq by default, correctly;

DONT try adding to /etc/resolv.conf

DONT add anything in /etc/network/interfaces

DONT create files in /etc/resolvconf/resolv.conf.d/tail

edit /etc/dhcp/dhclient.conf and add or uncomment/change the prepend line, thus

#prepend domain-name-servers 127.0.0.1;
prepend domain-name-servers 8.8.8.8, 208.67.222.222;
request subnet-mask, broadcast-address, time-offset, routers,

nm-tool output should now list those additional dns servers.

  IPv4 Settings:
    Address:         192.168.2.200
    Prefix:          24 (255.255.255.0)
    Gateway:         192.168.2.254

    DNS:             8.8.8.8
    DNS:             208.67.222.222
    DNS:             192.168.2.254