Adding a Public IPv6 Address on a Dedicated Server (Ubuntu 20.04)

For Dedicated Servers

This article explains how to add an additional, public IPv6 address on a Dedicated Server where Ubuntu 20.04 is installed.

To configure an additional public IPv6 address in Ubuntu 20.04, please proceed as follows:

Requirements

In the Cloud Panel, you have assigned an additional public IPv6 address to your server.
You have logged on to the server as an administrator.

Check which network interface is in use and enter the following command:
[root@localhost ~]# ip addr
Open the /etc/network/interfaces file in the vi Editor.
[root@localhost ~]# vi /etc/network/interfaces

Notes

The vi Editor has a command mode and an insert mode. To switch to input mode, press [i] on your keyboard. You can now insert the required content or make the required changes. Press the [ESC] key on your keyboard to exit the input mode.
To exit vi and save the file, type the command :wq, then press Enter.

Replace the entries with the following information:
auto lo eth0
iface lo inet loopback

allow-hotplug eth0
iface eth0 inet static
address Main IPv4 ADDRESS/32

iface eth0 inet6 manual
pre-up sleep 5
up dhclient -6 -nw -v eth0
post-up sleep 5; /sbin/ip -family inet6 route add default via fe80::1 dev eth0
pre-down /sbin/ip -family inet6 route del default via fe80::1 dev eth0
down dhclient -6 -r -v eth0

auto eth0:0
iface eth0:0 inet6 static
accept_ra 0
address Additional IPv6 Address/64

Note

For each additional IPv6 address, you need to add an additional section that contains the information below. To do this, a consecutive number is simply appended to the interface name, starting with 1.

auto eth0:1
iface eth0:1 inet6 static
accept_ra 0
address Additional IPv6 Address/64

Example:

auto lo eth0
iface lo inet loopback

allow-hotplug eth0
iface eth0 inet static
address 217.160.244.147/24

iface eth0 inet6 manual
pre-up sleep 5
up dhclient -6 -nw -v eth0
post-up sleep 5; /sbin/ip -family inet6 route add default via fe80::1 dev eth0
pre-down /sbin/ip -family inet6 route del default via fe80::1 dev eth0
down dhclient -6 -r -v eth0

auto eth0:0
iface eth0:0 inet6 static
accept_ra 0
address 2001:8d8:1800:1a1::1/64

auto eth0:1
iface eth0:1 inet6 static
accept_ra 0
address 2001:8d8:1800:1a1::2/64

Save the file.
Restart the server.
To check if the additional public IPv6 address has been added, type the following command:
[root@localhost ~]# ip addr
The additional public IPv6 address will now be displayed. Example:
root@A34C022:~# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether ac:1f:6b:9b:22:44 brd ff:ff:ff:ff:ff:ff
inet 217.160.244.147/32 scope global dynamic eth0
valid_lft 42828sec preferred_lft 42828sec
inet6 2001:8d8:1800:1a1::2/64 scope global deprecated
valid_lft forever preferred_lft 0sec
inet6 2001:8d8:1800:1a1::1/128 scope global
valid_lft forever preferred_lft forever
inet6 fe80::ae1f:6bff:fe9b:2244/64 scope link
valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
link/ether ac:1f:6b:9b:22:45 brd ff:ff:ff:ff:ff:ff