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.
Note: OVHcloud is providing you with services for which you are responsible, with regard to their configuration and management. You are therefore responsible for ensuring they function correctly. This guide is designed to assist you in common tasks as much as possible.
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 see that you already have the first (main) IPv6 configured out of the box.
The default gateway for your IPv6 block (IPv6_GATEWAY) is usually xxxx.xxxx.xxxx.xxFF:FF:FF:FF:FF.
For example:
- The IPv6 address of the server is 2607:5300:60:62ac::/64. The IPv6_GATEWAY will therefore be 2607:5300:60:62FF:FF:FF:FF:FF.
- The IPv6 address of the server is 2001:41D0:1:46e::/64. The IPv6_GATEWAY will therefore be 2001:41D0:1:4FF:FF:FF:FF:FF.
The safest way to retrieve the networking information for your server is to use the OVHcloud API. Execute the following API call, indicating the internal server name (example: ns3956771.ip-169-254-10.eu):
Debian and Debian-based operating systems
Before following the steps below, we strongly suggest that you disable IPv6 autoconf and router advertising to prevent known issues. You can do so by adding the following lines to your sysctl.conf file, which is located in /etc/sysctl.conf:
net.ipv6.conf.all.autoconf=0
net.ipv6.conf.all.accept_ra=0
Once this has been done, you can apply those rules by executing the following command: sudo sysctl -p. If it worked, you will see the lines you added to /etc/sysctl.conf in the output.
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/network/interfaces. Use the command line to locate the file and open it for editing. As a best practice, we recommend backing up the file 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
This example has been made with CentOS 7. Results may vary when using other Redhat derivatives.
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
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/systemd/network. For demonstration purposes, our file is called 50-default.network.
Step 3: Amend the network configuration file
Using a text editor, amend the file by adding the following lines to the relevant sections as shown in the example below:
[Network]
Destination=Gateway_Address
[Address]
Address=IPv6_Address/64
[Route]
Destination=Gateway_Address
Scope=link
To add multiple IPv6 addresses, add multiple [Address] sections.
[Address]
Address=IPv6_Address_2/64
[Address]
Address=IPv6_Address_3/64
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=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 2019
Step 1: Use RDP to connect to your server
Find more information in this guide.
Step 2: Open your server’s network configuration
First, from Server Manager, click Local Server on the left-hand column. Click the line that says IPv4 address assigned by DHCP, IPv6 enabled next to your public NIC ("Ethernet" in our example).
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.