ip address / network configuration

[Tom H]

On Wed, Jan 5, 2011 at 9:47 PM, Carlos S <neubyr at gmail.com> wrote:
>
> I have a Ubuntu 10.10 desktop edition installed with DHCP for
> IP/network configuration. How do I assign a static IP addresses to a
> network interfaces? Also, How can one configure multi-homed network in
> Ubuntu?
>
> A quick google search led me to following examples, where replacement
> of existing DHCP line is told.
> http://www.ubuntugeek.com/change-ubuntu-system-from-dhcp-to-a-static-ip-address.html
> http://www.howtogeek.com/howto/ubuntu/change-ubuntu-server-from-dhcp-to-a-static-ip-address/
>
> Interestingly I don't have any such DHCP config line in my system's
> '/etc/network/interfaces'. Following is what I have:
> {{
> auto lo
> iface lo inet loopback
> }}}
>
> So where is my existing IP address config?
>
> Also, if I edit network config in GUI then it is not written in
> interfaces file, although the config seems to be applied. Any
> elaboration on this network config would be really helpful.
>
> I have done this on CentOS and typically it is done in
> /etc/syconfig/networking-scripts/ifcfg-eth0.

When you edit the network configuration in the GUI, you're editing
Network Manager's configuration and that configuration isn't held in
the classical Debian equivalent of
"/etc/sysconfig/networking-scripts/ifcfg-eth0",
"/etc/network/interfaces". Unless you change a value
"/etc/NetworkManager/nm-settings", NM'll not bring your NICs up if
"/etc/network/interfaces" has more in it in it than what you have
posted above.

In Ubuntu, if you want to use "/etc/network/interfaces", you can't
"chkconfig NetworkManager off" and "chkconfig network on" as in
RHEL/CentOS/Fedora; you have to uninstall NM. Once you've done that,
you can follow the guides above.