While deploying a couple of Ubuntu Servers, I ran into an interesting problem. The servers obtained an IPv6 address even though during setup I had specified an IPv4 address. Lets just say after I rebooted I could get online but the purpose for an IPv4 address was defeated since I could not see myself remembering what the IPv6 address was. Detailed below are the steps needed to disable IPV6 and setup a static IPv4 address on an Ubuntu 12.04 server. This should work if on both physical and virtual servers.
First things first we will edit the sysctl.conf file. in your terminal issues the following command:
sudo nano /etc/sysctl.conf.
This should open the file ... Add the following lines to the end of the file:
#IPv6 configuration
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1
Then ctrl + o to save
Then ctrl + x to exit
Now restart the sysctl service by doing:
sudo sysctl -p
This should display the attend lines ...
You can verify that IPV6 is disabled by running the command
ip addr
or
ifconfig
Now that IPV6 is disabled run the following command to setup a static address using IPv4
sudo nano /etc/networking/interfaces
The file should tell you that it is using an auto configured IPv6 address for auto eth0
Change the line that reads
iface eth0 inet6 auto
to match the lines below
auto eth0
iface eth0 inet static
address 10.11.11.11
netmask 255.255.255.0
network 10.11.11.0
broadcast 10.11.11.255
gateway 10.11.11.1
Remember that the addresses used above are mine ... replace them with yours
ctrl + o to save
ctrl + x to exit
Now reboot the server....
sudo reboot now
When you are up and running again, you will have your server using a static IPv4 address.
