Configuring IPv6 on dedicated servers

Last updated 26th August 2022

Objective

Internet Protocol version 6 (IPv6) is the latest version of the Internet Protocol (IP). It is designed to address the long-anticipated address exhaustion of its predecessor, IPv4, by using 128-bit addresses instead of 32-bit addresses. Every OVHcloud dedicated server comes with a /64 IPv6 block. This represents over 18 quintillion IP addresses that you can use at your convenience.

This guide explains how to configure IPv6 addresses on your server using various examples.

Requirements

• A dedicated server in your OVHcloud account
• All your IPv6 information (prefix, gateway etc.)
• Basic knowledge of SSH and networking

Instructions

If you are using an OVHcloud-provided Linux OS template to install your server, you will need to configure the first (main) IPv6 on the server.

For example, if we have assigned to your server the IPv6 range: 2607:5300:xxxx:xxxx::/64 you may use as main IPv6 of your server the IPv6: 2607:5300:xxxx:xxxx::1/64.

If you want to have more than one IPv6 configured on your server (or want to use it on a VM) you will need to have an Additional IP configured with a vMAC. Otherwise, the IPv6 cannot be routed by our routers/switches.

Debian and Debian-based operating systems

Step 1: Use SSH to connect to your server

Find more information in this guide.

Step 2: Open your server's network configuration file

Your server's network configuration file is either located in /etc/network/interfaces or /etc/network/interfaces.d. Use the command line to locate the file and open it for editing. Also consider creating a backup first.

Step 3: Amend the network configuration file

Amend the file so that it looks like the example below. In this example, the network interface is called eth0. The interface on your server may differ.

iface eth0 inet6 static 
    address YOUR_IPv6 
    netmask 128

post-up /sbin/ip -f inet6 route add IPv6_GATEWAY dev eth0 
post-up /sbin/ip -f inet6 route add default via IPv6_GATEWAY 
pre-down /sbin/ip -f inet6 route del IPv6_GATEWAY dev eth0
pre-down /sbin/ip -f inet6 route del default via IPv6_GATEWAY

Additional IPv6 addresses can be added by up /sbin/ifconfig eth0 inet6 add YOUR_2nd_IPv6/64 lines in the file.

Step 4: Save the file and apply the changes

Save your changes to the file and then restart the network or reboot your server to apply the changes.

Step 5: Test the IPv6 connectivity

You can test the IPv6 connectivity by running the commands shown below:

ping6 -c 4 2001:4860:4860::8888

>>> PING 2001:4860:4860::8888(2001:4860:4860::8888) 56 data bytes
>>> 64 bytes from 2001:4860:4860::8888: icmp_seq=1 ttl=55 time=23.6 ms
>>> 64 bytes from 2001:4860:4860::8888: icmp_seq=2 ttl=55 time=23.8 ms
>>> 64 bytes from 2001:4860:4860::8888: icmp_seq=3 ttl=55 time=23.9 ms
>>> 64 bytes from 2001:4860:4860::8888: icmp_seq=4 ttl=55 time=23.8 ms

>>> --- 2001:4860:4860::8888 ping statistics ---
>>> 1 packets transmitted, 1 received, 0% packet loss, time 0ms
>>> rtt min/avg/max/mdev = 23.670/23.670/23.670/0.000 ms

If you are not able to ping this IPv6 address, check your configuration and try again. Also ensure that the machine you are testing from is connected with IPv6. If it still does not work, please test your configuration in Rescue mode.

Fedora 26 and above

Step 1: Use SSH to connect to your server

Find more information in this guide.

Step 2: Open your server's network configuration file

Your server's network configuration file is located in /etc/sysconfig/network-scripts/ifcfg-eth0. Use the command line to locate this file and open it for editing.

Step 3: Amend the network configuration file

Amend the file so that it looks like the example below. In this example, the network interface is called eth0. The interface on your server may differ. Also, we have omitted the IPv4 configuration to avoid confusion, but the IPv6 configuration is made in the same configuration file.

IPV6INIT=yes
IPV6_AUTOCONF=no
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6ADDR=YOUR_IPv6/64
IPV6ADDR_SECONDARIES=YOUR_2nd_IPv6/64 YOUR_3rd_IPv6/64
IPV6_DEFAULTGW=IPv6_GATEWAY

If you need more IPv6 addresses on the machine, add them in the IPV6ADDR_SECONDARIES line, separated by whitespace.

Step 4: Save the file and apply the changes

Save your changes to the file and then restart the network or reboot your server to apply the changes.

Step 5: Test the IPv6 connectivity

You can test the IPv6 connectivity by running the commands shown below:

ping6 -c 4 2001:4860:4860::8888

>>> PING 2001:4860:4860::8888(2001:4860:4860::8888) 56 data bytes
>>> 64 bytes from 2001:4860:4860::8888: icmp_seq=1 ttl=55 time=23.6 ms
>>> 64 bytes from 2001:4860:4860::8888: icmp_seq=2 ttl=55 time=23.8 ms
>>> 64 bytes from 2001:4860:4860::8888: icmp_seq=3 ttl=55 time=23.9 ms
>>> 64 bytes from 2001:4860:4860::8888: icmp_seq=4 ttl=55 time=23.8 ms

>>> --- 2001:4860:4860::8888 ping statistics ---
>>> 1 packets transmitted, 1 received, 0% packet loss, time 0ms
>>> rtt min/avg/max/mdev = 23.670/23.670/23.670/0.000 ms

If you are not able to ping this IPv6 address, check your configuration and try again. Also ensure that the machine you are testing from is connected with IPv6. If it still does not work, please test your configuration in Rescue mode.

FreeBSD

Step 1: Use SSH to connect to your server

Find more information in this guide.

Step 2: Open your server's network configuration file

Your server's network configuration file is located in /etc/rc.conf. Use the command line to locate this file and open it for editing.

Step 3: Amend the network configuration file

Amend the file so that it looks like the example below. In this example, the network interface is called em0. The interface on your server may differ.

IPv6_activate_all_interfaces="YES" 
IPv6_defaultrouter="IPv6_GATEWAY" 
ifconfig_em0_IPv6="inet6 IPv6_Address prefixlen 64"
ifconfig_em0_alias0="inet6 IPv6_Address_2 prefixlen 64"
ifconfig_em0_alias1="inet6 IPv6_Address_3 prefixlen 64"

Step 4: Save the file and reboot the server

Save your changes to the file and then restart the network or reboot your server to apply the changes.

Step 5: Test the IPv6 connectivity

You can test the IPv6 connectivity by running the commands shown below:

ping6 -c 4 2001:4860:4860::8888

>>> PING 2001:4860:4860::8888(2001:4860:4860::8888) 56 data bytes
>>> 64 bytes from 2001:4860:4860::8888: icmp_seq=1 ttl=55 time=23.6 ms
>>> 64 bytes from 2001:4860:4860::8888: icmp_seq=2 ttl=55 time=23.8 ms
>>> 64 bytes from 2001:4860:4860::8888: icmp_seq=3 ttl=55 time=23.9 ms
>>> 64 bytes from 2001:4860:4860::8888: icmp_seq=4 ttl=55 time=23.8 ms

>>> --- 2001:4860:4860::8888 ping statistics ---
>>> 1 packets transmitted, 1 received, 0% packet loss, time 0ms
>>> rtt min/avg/max/mdev = 23.670/23.670/23.670/0.000 ms

If you are not able to ping this IPv6 address, check your configuration and try again. Also ensure that the machine you are testing from is connected with IPv6. If it still does not work, please test your configuration in Rescue mode.

Ubuntu 18.04 and 20.04

Step 1: Use SSH to connect to your server

Find more information in this guide.

Step 2: Open your server's network configuration file

Open the network configuration file located in /etc/netplan. For demonstration purposes, our file is called '50-cloud-init.yaml'.

Step 3: Amend the network configuration file

Using a text editor, amend the '50-cloud-init.yaml' file by adding the following lines to the relevant sections as shown in the example below.

Replace the generic elements (i.e. YOUR_IPV6, IPV6_PREFIX and IPV6_GATEWAY) as well as the network interface (if your server is not using enp1s0) with your specific values.

network:
    version: 2
    ethernets:
        enp1s0:
            dhcp4: true
            match:
                macaddress: 00:04:0p:8b:c6:30
            set-name: enp1s0
            addresses:
              - YOUR_IPV6/IPv6_PREFIX
            gateway6: IPv6_GATEWAY
            routes:
                - to: IPv6_GATEWAY
                  scope: link

Ubuntu 21.10 and 22.04

The configuration file should look like the example below:

network:
    version: 2
    ethernets:
        enp1s0:
            dhcp4: true
            match:
                macaddress: 00:04:0p:8b:c6:30
            set-name: enp1s0
            addresses:
              - YOUR_IPV6/IPv6_PREFIX
            routes:
                - to: ::/0
                  via: IPv6_GATEWAY
                - to: IPv6_GATEWAY
                  scope: link

Step 4: Test and apply the configuration

You can test your configuration using this command:

netplan try

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

netplan apply

Step 5: Test the IPv6 connectivity

You can test the IPv6 connectivity by running the commands shown below:

ping6 -c 4 2001:4860:4860::8888

PING 2001:4860:4860::8888(2001:4860:4860::8888) 56 data bytes
64 bytes from 2001:4860:4860::8888: icmp_seq=1 ttl=57 time=4.07 ms
64 bytes from 2001:4860:4860::8888: icmp_seq=2 ttl=57 time=4.08 ms
64 bytes from 2001:4860:4860::8888: icmp_seq=3 ttl=57 time=4.08 ms
64 bytes from 2001:4860:4860::8888: icmp_seq=4 ttl=57 time=4.07 ms

--- 2001:4860:4860::8888 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3003ms
rtt min/avg/max/mdev = 4.075/4.079/4.083/0.045 ms

Windows Server 2012

Step 1: Use RDP to connect to your server

Find more information in this guide.

Step 2: Open your server's network configuration

First, right-click on the network icon in the notification area to go to the Network and Sharing Center.

Click Change adapter settings.

Right-click your network adapter, then click Properties.

Select Internet Protocol Version 6, then click Properties.

Step 3: Amend the network configuration

Enter your IPv6 configuration (IPv6 address and Default Gateway) and click OK.

Troubleshooting

If after testing your connection you are still experiencing problems, please create a support request to review your configurations. It is necessary to provide:

• The operating system name and version you are using on your server.
• The name and directory of the network configuration file.
• The content of that file.

Go further

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

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