Linode additional IPv6 address with Netplan on Ubuntu 24.04 configuration guide
Note that the configuration for additional IPv6 address varies depending on the distribution and the version of the distribution. Refer to the references if unsure.
Disable network helper
Network helper automatically configures the network at boot, which overwrites anything in Netplan. We need to disable it.
Log in to Cloud Manager and open your Linode. Navigate to Configurations > Edit > Filesystem/Boot Helpers, turn off Auto-configure networking and click Save Changes.
SSH into your Linode and delete /etc/systemd/network/05-eth0.network.
The default Netplan config
In your Linode, cd into /etc/netplan/ and you’ll find the default Netplan config file 01-netcfg.yaml with the following contents:
# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
version: 2
renderer: networkd
ethernets:
eth0:
dhcp4: yes
Configure the primary IPv4 address through DHCP
The primary IPv4 address can be configured automatically through DHCP with the following configuration:
...
ethernets:
eth0:
dhcp4: yes
Configure the primary IPv6 address through SLAAC
The primary IPv6 address can be configured automatically through SLAAC with the following configuration:
...
ethernets:
eth0:
accept-ra: yes # Allow router advertisements
ipv6-privacy: no # Disable IPv6 privacy extensions
Configure additional IPv6 addresses
Additional IPv6 addresses can be added by adding addressses entries beneath the interface. IPv6 addresses (and their associated prefixes) should be surrounded by quotation marks. For Linodes, the default fateway for all IPv6 addresses is fe80::1.
...
ethernets:
eth0:
addresses:
- "[ip-address]/[prefix]"
routes:
- to: default
via: "[default-gateway]"
Change the DNS resolvers
The DNS resolvers can be set using the nameservers option. However, if dhcp4 is set to yes, dhcp4-overrides should be configured as follows to prevent the DNS configuration being overwritten by DHCP:
...
ethernets:
eth0:
dhcp4: yes
dhcp4-overrides:
use-dns: no
nameservers:
addresses:
- 203.0.113.1
- 203.0.113.2
- 203.0.113.3
Example configuration
Suppose that the IPv6 range 2400::/64 is delegated to you, you would like to add 2400::1 to your server, and the default gateway for the server is fe80::1:
# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
version: 2
renderer: networkd
ethernets:
eth0:
dhcp4: yes # Configuring the primary IPv4 address through DHCP
accept-ra: yes # Configuring the primary IPv6 address through SLAAC
ipv6-privacy: no # Configuring the primary IPv6 address through SLAAC
addresses:
- "2400::1/64"
routes:
- to: default
via: "fe80::1"
Apply the changes
Save the configuration then run the following command:
sudo netplan apply --debug
Reboot
sudo reboot
Verify the configuration:
ip -6 addr
References
https://techdocs.akamai.com/cloud-computing/docs/manual-network-configuration-on-a-compute-instance
https://techdocs.akamai.com/cloud-computing/docs/network-configuration-using-netplan
https://docs.digitalocean.com/products/networking/ipv6/how-to/enable/