Info Linux and Microcontroller

NetworkManager program provided in Ubuntu 8.10 is mainly aiming to provide a simplified Internet connection. NetworkManager is best for home users and simple internet users. If you want to use a fixed IP address it makes problem, the static IP setting will be work only upto the next restart. After reboot you can't see the Fixed IP. It will reset to DHCP.

Solution for this problem

Uninstall NetworkManager is the only solution
sudo apt-get remove network-manager network-manager-gnome

After that configure manualy the interfaces

Modify the following file: /etc/networks/interfaces.
gksudo gedit /etc/network/interfaces

You can see the following in this file
auto lo
iface lo inet loopback

keep it as such

add the following

auto eth0
iface eth0 inet static
address 192.168.0.1
netmask 255.255.255.0

if you have morethan one network card and
you want to set a DHCP in eth1 use the following

auto eth1
iface eth1 inet dhcp

Now Restart the network

sudo /etc/init.d/networking restart