Still going through it - one obvious difference is mine brings up a DHCPv6 Client:
$this->bbcode_second_pass_code('', 'Oct 12 23:41:42 nas systemd-networkd[439]: NDISC: Sent Router Solicitation, next solicitation in 4s
Oct 12 23:41:42 nas systemd-networkd[439]: NDISC: Received Router Advertisement: flags MANAGED preference medium lifetime 1800 sec
Oct 12 23:41:42 nas systemd-networkd[439]: NDISC: Invoking callback for 'router' event.
Oct 12 23:41:42 nas systemd-networkd[439]: DHCPv6 CLIENT: Started in Managed mode
Oct 12 23:41:42 nas systemd-networkd[439]: eth0: Acquiring DHCPv6 lease on NDisc request
')then I get fairly regular$this->bbcode_second_pass_code('', 'Oct 12 23:49:35 nas systemd-networkd[439]: DHCPv6 CLIENT: Sent SOLICIT
Oct 12 23:49:35 nas systemd-networkd[439]: DHCPv6 CLIENT: Next retransmission in 1min 58s
Oct 12 23:49:59 nas systemd-networkd[439]: NDISC: Received Router Advertisement: flags MANAGED preference medium lifetime 1800 sec
Oct 12 23:49:59 nas systemd-networkd[439]: NDISC: Invoking callback for 'router' event.
Oct 12 23:49:59 nas systemd-networkd[439]: eth0: Acquiring DHCPv6 lease on NDisc request
')
Which sets the IPv6 addresses - so my systemd-networkd is operating very differently from yours. Do you have a line like:
$this->bbcode_second_pass_code('', 'Oct 12 23:41:40 nas systemd-networkd[439]: eth0: IPv6 successfully enabled
Oct 12 23:41:40 nas systemd-networkd[439]: Setting '/proc/sys/net/ipv6/conf/eth0/proxy_ndp' to '0'
Oct 12 23:41:40 nas systemd-networkd[439]: Setting '/proc/sys/net/ipv4/ip_forward' to '1'
Oct 12 23:41:40 nas systemd-networkd[439]: Setting '/proc/sys/net/ipv6/conf/all/forwarding' to '1'
Oct 12 23:41:40 nas systemd-networkd[439]: Setting '/proc/sys/net/ipv6/conf/eth0/use_tempaddr' to '2'
Oct 12 23:41:40 nas systemd-networkd[439]: Setting '/proc/sys/net/ipv6/conf/eth0/accept_ra' to '0'
Oct 12 23:41:40 nas systemd-networkd[439]: LLDP: Started LLDP client
Oct 12 23:41:40 nas systemd-networkd[439]: eth0: Started LLDP.
Oct 12 23:41:40 nas systemd-networkd[439]: eth0: Setting address genmode for link
') which for me disables the kernel RA by setting accept_ra to zero.
What do you have in your [NETWORK] section of the interface definition. The man says:
$this->bbcode_second_pass_code('', 'DHCP=
Enables DHCPv4 and/or DHCPv6 client support. Accepts "yes", "no", "ipv4", or "ipv6". Defaults to "no".
Note that DHCPv6 will by default be triggered by Router Advertisement, if that is enabled, regardless of this parameter. By enabling DHCPv6 support explicitly, the DHCPv6 client will be started regardless of the presence of routers on the link, or what flags the routers pass. See "IPv6AcceptRA=".
Furthermore, note that by default the domain name specified through DHCP is not used for name resolution. See option UseDomains= below.
See the [DHCPv4] or [DHCPv6] sections below for further configuration options for the DHCP client support.')