====== How to set a Static IP in Ubuntu ======

=== Prior to 17.10 ===
First, we need to shutdown the interface:<code bash>
sudo ifdown eth0
</code>

To specify a static connection we need to change the Ethernet's interface configuration in ''/etc/network/interfaces'':
<code>
iface eth0 inet static
address 192.168.0.101
gateway 192.168.0.254
netmask 255.255.255.0
dns-nameservers 8.8.8.8 8.8.4.4
</code>

If you are using IPv6 static addresses, add an additional block it ''/etc/network/interfaces'':<code>
iface eth0 inet6 static
address 2001:db8:ff01:6fe::1e3a
netmask 64
gateway 2001:db8:ff01:6fe::1
dns-nameservers 2001:4860:4860::8888 2001:4860:4860::8844
</code>

Keep in mind that only 3 name servers will end up in the ''resolv.conf'' file if you use both the IPv4 block and the IPv6 block above. This is an issue related to the ''libc'' resolver limitation of a maximum of 3 name servers...

Finally, restart the interface to put the new settings into effect:
<code bash>
sudo ifup eth0
</code>

=== 17.10 and after ===

<code>
cat > /tmp/01-netcfg.yaml << EOF
network:
  version: 2
  renderer: networkd
  ethernets:
    eth0:
     dhcp4: no
     dhcp6: no
     accept-ra: no
     addresses:
     - 192.168.1.222/24
     - fd35:cf89:7706:1e92::222/64
     gateway4: 192.168.1.1
     gateway6: fd35:cf39:7706:1e92:1
     nameservers:
       addresses:
       - 8.8.8.8
       - 8.8.4.4
       search:
       - lab.example.com
       - home.example.com
EOF
 
sudo mv /tmp/01-netcfg.yaml /etc/netplan/
sudo rm /etc/netplan/50-cloud-init.yaml
</code>

Once ready apply changes with:

<code bash>
sudo netplan --debug apply
</code>