1.
onfigure Networking on Ubuntu
During the installation of Ubuntu on your server an IP address was
most likely obtained automatically. This dynamic IP address assignment
will need to be changed to a static IP address. This section will cover
the simple network configuration changes needed to set a static IP
network address for your server. For this section, the directions assume
the configuration is for a node with only one interface (eth0) after a
default installation.
Note
These instructions assume that the reader is familiar with opening,
editing and saving files at the command line. Please consult your OS
documentation if you need assistance with these tasks.
Most Linux systems have a few commands that can be used to find out what the current network configuration is, for example:
You can also use variations of the
ip command:
Basic network configuration and hostname on a Ubuntu system are
stored in several files which must be edited to create a working
configuration:
/etc/network/interfaces describes the network interfaces/etc/hostname configures the nameserver credentials/etc/hosts resolves IP addresses to hostnames
Once the new configuration is saved the interface must be restarted.
Changing Network Configuration
Below is an example of a static IP configuration on a system with
only one Ethernet interface (eth0) and 10.0.0.41/24 for the IP address.
Opening the
/etc/network/interfaces file will produce:
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
auto eth0
iface eth0 inet static
address 10.0.0.41
netmask 255.255.255.0
network 10.0.0.0
broadcast 10.0.0.255
gateway 10.0.0.1
dns-nameservers 10.0.0.1 8.8.8.8
dns-domain acme.com
dns-search acme.com
- Open your
/etc/network/interfaces file, locate the:
- "iface eth0..." line and change dynamic to static
- address line and change the address to the static IP address
- netmask line and change the address to the correct subnet mask
- gateway line and change the address to the correct gateway address
- dns-nameservers line and change (or add) the nameserver information
If you aren't certain which IP address, subnet mask, gateway or
dns-nameservers you need, please consult with your network administrator
for the correct information.
When you are happy with your configuration restart the interface with
the command below. If you are connected using SSH you will lose your
connection, re-connect using the new IP address:
Changing the Hostname
To change the hostname to your preferred node name (example: prodnode01), you have to edit the
/etc/hostname file:
Adding the FQDN (Hostname)
To ensure your server traffic will be routing correctly add the
server's Fully Qualified Domain Name (FQDN) and IP address to the hosts
file. Open the
/etc/hosts file and add a line with the static IP address and the FQDN, similar to the example shown below:
192.168.0.0 prodnode01.acme.com
With all your files edited and saved, you should reboot so the new name and configuration will be used.
Reboot the system and then use ifconfig or ipaddr to confirm that
your new configuration is available. You can also use hostname -f to
verify the hostname change,
