For the archive. Cumulus support was able to help me on this issue. The problem was that I'm using VRRP on top of the VLAN interface, so the IPv6 ND settings had to be configured on the VRRP interface, and not on the underlying VLAN interface: | interface vrrp6-63-3 | ipv6 nd managed-config-flag | ipv6 nd ra-interval 5 | no ipv6 nd suppress-ra So once this was set, everything seems to work fine. I hope the ifindex (63) in the interface name won't change, but that is a separate issue... Thanks, Thomas