I'm currently configuring the network interfaces for a Ubuntu 18.04 server, using netplan with the networkd backend. My hosting provider provides me with an IPv4 and an IPv6 for this server, however the IPv6 isn't automatically configured, which I'm currently trying to do.

My netplan configuration file is the following:

    version: 2
            dhcp4: true
            dhcp6: true
                macaddress: xx:xx:xx:xx:xx:xx
            set-name: ens3

When running netplan apply, the allocated IPv6 doesn't appear in ip addr. I thought this would be because maybe my provider doesn't provide DHCP for IPv6, but if I remember correctly (from setting up a different server) that would show an error in the systemd-networkd logs, however all I can see there is:

systemd[1]: Starting Network Service...
systemd-networkd[9367]: ens3: Gained IPv6LL
systemd-networkd[9367]: Enumeration completed
systemd[1]: Started Network Service.
systemd-networkd[9367]: lo: Link is not managed by us
systemd-networkd[9367]: ens3: DHCPv4 address xxx.xxx.xxx.xxx/32 via yyy.yyy.yyy.yyy
systemd-networkd[9367]: ens3: Configured

Which doesn't show anything I understand as an error when trying to get the IPv6 via DHCP (only Gained IPv6LL seems to be related to IPv6, but a quick search shows me that it doesn't seem to be related).

Did I mess something up in my configuration file?

  • 2
    Please install the ndisc6 toolkit using the package manager, and then run sudo rdisc6 -1 ens3. If IPv6 routing is available, you should get a response within a few seconds, but you might have to wait up to 30 seconds or so. The response will tell you whether DHCPv6 is available (fields Stateful address conf. and Stateful other conf.), and whether or not other address determination schemes like SLAAC are allowed by the router (Autonomous address conf.). If you cannot get this router advisory, make sure you aren't excessively filtering ICMPv6. – telcoM Jul 16 at 11:08

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.