How to configure IPv6 connectivity using systemd-networkd

Before you start

To complete the actions presented below, you must have:

• A Dedibox account logged into the console
• A Dedibox dedicated server
• Requested a /48 IPv6 prefix

How to configure IPv6 on Ubuntu

Ubuntu uses netplan since the release of Ubuntu 18.04 LTS as network configuration tool. It replaces the classical network configuration with new configuration files, written in YAML format, and located in the /etc/netplan directory. For more information regarding netplan, refer to the official documentation.

1. Open the default configuration file /etc/netplan/01-netcfg.yaml in a text editor, and edit it as follows:

   # This file describes the network interfaces available on your system
   # For more information, see netplan(5).
   network:
   version: 2
   renderer: networkd
   ethernets:
       enp1s0:
       dhcp4: no
       dhcp6: no
       addresses:
       - "aaa.bbb.ccc.ddd/24" # The main IP address of your Dedibox server
       - "2001:bc8:xxxx:xxx::x/64" # An IP address from your IPv6 block and its subnet mask /64, replace placeholder values
       gateway4: aaa.bbb.ccc.1 # The gateway is the IPv4 address of your Dedibox, ending on .1
       nameservers:
       addresses: [ "51.159.47.28", "51.159.47.26" ] # Replace the IP of the DNS cache server with the one located in the same physical location as your machine for optimal performances (https://www.scaleway.com/en/docs/console/account/reference-content/scaleway-network-information/#dns-cache-servers)
       routes:
       - to: 0.0.0.0
           via: aaa.bbb.ccc.1
           on-link: true
   

   Remember to replace enp1s0 with the proper name of your internet interface.

   Note

   The configuration example above is valid for the main IP address of your Dedibox server. If you want to use IPv6 on a virtual machine, remember to use the unique gateway for the failover IPv4.

2. Check and validate your configuration file.

   sudo netplan –debug
   

3. Activate the new configuration:

   sudo netplan apply
   

How to configure IPv6 on Linux with systemd-networkd

systemd-networkd is the network manager of systemd. It is provided natively on most Linux distributions and can be used for the configuration of IPv6 with its DHCPv6 client feature.

1. Run the ip link show command to find the name of your public internet interface. Make sure to store it, as it will be required in the next steps.
2. Run the following command to create a backup of the current network configuration and configure systemd-networkd:

   sudo mv /etc/systemd/network/eno1.network /etc/systemd/network/eno1.network.bkp
   

3. Run the following command to enable systemd-networkd.

   systemctl enable systemd-networkd.service
   

4. Create a new file called <interface_name>.network and open it in a text editor.

   sudo nano /etc/systemd/network/eno1.network
   

5. Open the file in a text editor and paste the following content. Make sure to replace the values in the example with your own and save them before exiting the text editor.

   [Match]
   #The name must correspond to your interface name
   Name=eno1
   [Network]
   DHCP=ipv6
   IPv6AcceptRA=yes
   # IPv4 of the Dedibox, change netmask to /32 if failover IPv4
   Address=<ipv4_of_your_dedibox>/24
   # IPv6 of the Dedibox
   Address=2001:bc8:xxxx:xxx::x/64
   [Route]
   # The IPv4 gateway is either your Dedibox IP ending on .1 (i.e. x.y.z.1) for the physical host or 62.210.0.1 for any VM running on a Dedibox
   Gateway=<gateway_ipv4>
   GatewayOnlink=yes
   [DHCP]
   ClientIdentifier=duid-only
   DUIDType=link-layer
   # Scaleway Dedibox DUID without the DUID-LL "00:03" at the beginning
   DUIDRawData=<Scaleway IPv6 DUID>
   [DHCPv6]
   UseAddress=no
   WithoutRA=solicit
   [IPv6AcceptRA]
   DHCPv6Client=always
   UseOnLinkPrefix=False
   UseAutonomousPrefix=False
   

6. Run the following command to activate the new configuration.

   systemctl start systemd-networkd