Configure a Floating IP

If you are using more than one floating IP, then the number on the interface (eth0:1) will be increased (example eth0:2).

On Debian based distributions (Ubuntu - before 20.04, Debian):

Create the configuration file and open an editor

touch /etc/network/interfaces.d/60-my-floating-ip.cfg
nano /etc/network/interfaces.d/60-my-floating-ip.cfg

Paste the following configuration into the editor and replace your.Float.ing.IP with your Floating IP

IPv4:

 auto eth0:1
 iface eth0:1 inet static
     address your.Float.ing.IP
     netmask 32

IPv6:

 auto eth0:1
 iface eth0:1 inet6 static
     address one IPv6 address of the subnet, e.g. 2a01:4f9:0:2a1::2
     netmask 64

Now you should restart your network. Caution: This will reset your network connection

sudo service networking restart

Create the configuration file and open an editor

touch /etc/netplan/60-floating-ip.yaml
nano /etc/netplan/60-floating-ip.yaml

Paste the following configuration into the editor and replace your.Float.ing.IP with your Floating IP

IPv4:

 network:
   version: 2
   ethernets:
     eth0:
       addresses:
       - your.float.ing.ip/32

IPv6:

 network:
   version: 2
   ethernets:
     eth0:
       addresses:
       - your.float.ing.ip/64

Now you should restart your network. Caution: This will reset your network connection

sudo netplan apply

Create the configuration file and open an editor

touch /etc/sysconfig/network-scripts/ifcfg-eth0:1
vi /etc/sysconfig/network-scripts/ifcfg-eth0:1

Paste the following configuration into the editor and replace your.Float.ing.IP with your Floating IP

IPv4:

 BOOTPROTO=static
 DEVICE=eth0:1
 IPADDR=your.Float.ing.IP
 PREFIX=32
 TYPE=Ethernet
 USERCTL=no
 ONBOOT=yes

IPv6:

 BOOTPROTO=none
 DEVICE=eth0:1
 ONBOOT=yes
 IPV6ADDR=one IPv6 address of the subnet, e.g. 2a01:4f9:0:2a1::2/64
 IPV6INIT=yes

Now you should restart your network. Caution: This will reset your network connection

systemctl restart network