Configuring IPv6 on a Public Cloud instance

Last updated 15th November 2022

Objective

Internet Protocol version 6 (IPv6) is the latest version of Internet Protocol (IP). It is designed to resolve the long-anticipated exhaustion of IPv4 addresses, by using addresses made up of 128-bits rather than the standard 32-bits of IPv4.

Each Public Cloud instance is delivered with an IPv4 address and an IPv6 address.

By default, only the IPv4 address is configured.

This guide will show you how to configure an IPv6 address on a Public Cloud instance.

Requirements

• A Public Cloud instance (any model)
• Administrative access (root) via SSH or remote desktop (Windows) to your server
• A basic understanding of networking
• Access to the OVHcloud Control Panel

Instructions

Glossary

Here is a short glossary of the terms used in this tutorial:

Retrieve your network information.

Log in to the OVHcloud Control Panel and open your Public Cloud project. Then click on Instances in the left-hand menu.

Click on ... next to the corresponding instance and click on Instance details.

All the information you need is in the Networks section.

Examples of persistent configuration.

First of all, connect to your instance via SSH.

On Debian

If we assume that your interface is eth0, the configuration should look like this:

File to edit (with su privileges): /etc/network/interfaces

iface eth0 inet6 static
address YOUR_IPV6
netmask IPV6_PREFIX
post-up /sbin/ip -6 route add IPV6_GATEWAY dev eth0
post-up /sbin/ip -6 route add default via IPV6_GATEWAY dev eth0
pre-down /sbin/ip -6 route del default via IPV6_GATEWAY dev eth0
pre-down /sbin/ip -6 route del IPV6_GATEWAY dev eth0

Here is a concrete example:

iface eth0 inet6 static
address 2001:41d0:xxx:xxxx::999
netmask 128
post-up /sbin/ip -6 route add 2001:41d0:xxx:xxxx::111 dev eth0
post-up /sbin/ip -6 route add default via 2001:41d0:xxx:xxxx::111 dev eth0
pre-down /sbin/ip -6 route del default via 2001:41d0:xxx:xxxx::111 dev eth0
pre-down /sbin/ip -6 route del 2001:41d0:xxx:xxxx::111 dev eth0

On Ubuntu

The network configuration files are located in the /etc/netplan/ directory. First, create a copy of the IPv6 configuration file:

cd /etc/netplan
cp 50-cloud-init.yaml 51-cloud-init-ipv6.yaml

This allows you to separate the IPv6 configuration and easily revert the changes in case of an error.

If we assume that your interface is eth0, the configuration should look like this:

File to edit (with su privileges): /etc/netplan/51-cloud-init-ipv6.yaml

network:
    ethernets:
        eth0:
            dhcp6: false
            match:
                macaddress: fb:17:3r:39:56:75
            set-name: eth0
            addresses:
              - "YOUR_IPV6/IPv6_PREFIX"
            gateway6: "IPv6_GATEWAY"
            routes:
              - to: "IPv6_GATEWAY"
                scope: link
    version: 2

You can test your configuration using this command:

netplan try

If it is correct, apply it using the following command:

netplan apply

On RedHat / CentOS

If we assume that your interface is eth0, the configuration should look like this:

File to edit (with sudo privileges): /etc/sysconfig/network-scripts/ifcfg-eth0

IPV6INIT=yes
IPV6ADDR=YOUR_IPV6/IPV6_PREFIX
IPV6_DEFAULTGW=IPV6_GATEWAY

Here is a concrete example:

IPV6INIT=yes
IPV6ADDR=2001:41d0:xxx:xxxx::999
IPV6_DEFAULTGW=2001:41d0:xxx:xxxx::111

On Windows

Go to Network Connections in Windows.

Then go to Properties for your network card by right-clicking on it.

Next, click on IPv6, and Properties.

Lastly, enter your IPv6 details.

Diagnostic

Have you configured your IPv6, but found that nothing works?

There is a simple operation to determine whether the error is in your configuration, or on the OVHcloud network.

Firstly, put your instance into rescue-pro mode.

Next, use the template commands below to configure your IP non-persistently, replacing ‘YOUR_IPV6’, ‘IPV6_PREFIX’, etc. with your own details:

ip addr add YOUR_IPV6/IPV6_PREFIX dev eth0
ip -6 route add IPV6_GATEWAY dev eth0
ip -6 route add default via IPV6_GATEWAY dev eth0

Test your network again via a ping6, for example:

ping6 ipv6.google.com

If your instance responds, it is likely that there is an error in one of the steps taken for your initial configuration.

In any case, please feel free to reach out to our support team with the elements tested above, and we can perform an analysis on our end.

Go further

Join our community of users on https://community.ovh.com/en/.

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