Adding a Public IPv6 Address to a Dedicated Server (Debian 10)

For Dedicated Servers

This article explains how to add an additional, public IPv6 address on a Dedicated Server where Debian 10 is installed.

To configure an additional public IPv6 address in Debian 10, 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 file /etc/network/interfaces with the editor vi.
[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 information with the following:
auto lo eth0
iface lo inet loopback

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

iface eth0 inet dhcp
iface eth0 inet6 manual
pre-up sleep 5
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
up dhclient -6 -nw -v 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:

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug eth0
iface eth0 inet static
address 82.165.126.185/32

iface eth0 inet dhcp
iface eth0 inet6 manual
pre-up sleep 5
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
up dhclient -6 -nw -v eth0
down dhclient -6 -r -v eth0

auto eth0:0
iface eth0:0 inet6 static
accept_ra 0
address 2001:8d8:1801:818f::1/64

auto eth0:1
iface eth0:1 inet6 static
accept_ra 0
address 2001:8d8:1801:818f::2/64

Save the file.
Restart your 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@D364224:~# 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 3c:ec:ef:22:f1:34 brd ff:ff:ff:ff:ff:ff
inet 82.165.126.185/32 brd 82.165.126.185 scope global eth0
valid_lft forever preferred_lft forever
inet6 2001:8d8:1801:818f::2/64 scope global deprecated
valid_lft forever preferred_lft 0sec
inet6 2001:8d8:1801:818f::1/64 scope global deprecated
valid_lft forever preferred_lft 0sec
inet6 fe80::3eec:efff:fe22:f134/64 scope link
valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
link/ether 3c:ec:ef:22:f1:35 brd ff:ff:ff:ff:ff:ff