I have no idea why this is not working. I ran tcpdump -n -i eth0 icmp6 on a machine for at least 30 minutes and no router-adverts were seen, just router-solicitation and neighbor packets.
The config file looks right, service is running, restarting the service has no effect (if it was a boot ordering issue it would).
Also, the help text on the 'service router-advert' node is wrong.
[email protected]# sudo systemctl status radvd ● radvd.service - Router advertisement daemon for IPv6 Loaded: loaded (/lib/systemd/system/radvd.service; disabled; vendor preset: enabled) Active: active (running) since Mon 2020-04-20 18:24:23 CEST; 3h 43min ago Docs: man:radvd(8) Main PID: 2574 (radvd) Tasks: 2 (limit: 542) Memory: 1.0M CGroup: /system.slice/radvd.service ├─2574 /usr/sbin/radvd --logmethod stderr_clean └─2575 /usr/sbin/radvd --logmethod stderr_clean Apr 20 18:24:23 rt-home systemd[1]: Starting Router advertisement daemon for IPv6... Apr 20 18:24:23 rt-home radvd[2572]: config file, /etc/radvd.conf, syntax ok Apr 20 18:24:23 rt-home radvd[2573]: version 2.17 started Apr 20 18:24:23 rt-home systemd[1]: Started Router advertisement daemon for IPv6. Apr 20 18:24:36 rt-home systemd[1]: /lib/systemd/system/radvd.service:11: PIDFile= references path below legacy directory /var/run/, updating /var/run/radvd.pid → /run/radvd.pid; please update the unit f Apr 20 18:24:39 rt-home systemd[1]: /lib/systemd/system/radvd.service:11: PIDFile= references path below legacy directory /var/run/, updating /var/run/radvd.pid → /run/radvd.pid; please update the unit f [edit] [email protected]# sudo vi /etc/radvd.conf [edit] [email protected]# sudo systemctl reload radvd [edit] [email protected]# sudo systemctl restart radvd [edit] [email protected]# set service router-advert Possible completions: +> interface Interface to send DDNS updates for [REQUIRED] [edit] [email protected]# set service router-advert interface br0 interval max 60 [edit] [email protected]# commit [ service router-advert interface br0 interval max 60 ] [ service router-advert ] [edit] [email protected]# sudo systemctl status radvd ● radvd.service - Router advertisement daemon for IPv6 Loaded: loaded (/lib/systemd/system/radvd.service; disabled; vendor preset: enabled) Active: active (running) since Mon 2020-04-20 22:16:09 CEST; 24s ago Docs: man:radvd(8) Process: 6882 ExecStartPre=/usr/sbin/radvd --logmethod stderr_clean --configtest (code=exited, status=0/SUCCESS) Process: 6884 ExecStart=/usr/sbin/radvd --logmethod stderr_clean (code=exited, status=0/SUCCESS) Main PID: 6885 (radvd) Tasks: 2 (limit: 542) Memory: 900.0K CGroup: /system.slice/radvd.service ├─6885 /usr/sbin/radvd --logmethod stderr_clean └─6886 /usr/sbin/radvd --logmethod stderr_clean Apr 20 22:16:09 rt-home systemd[1]: Starting Router advertisement daemon for IPv6... Apr 20 22:16:09 rt-home radvd[6882]: config file, /etc/radvd.conf, syntax ok Apr 20 22:16:09 rt-home radvd[6884]: version 2.17 started Apr 20 22:16:09 rt-home systemd[1]: Started Router advertisement daemon for IPv6. [edit] [email protected]# show service router-advert interface br0 { hop-limit 64 interval { max 60 } managed-flag prefix 2001:db8::/64 { valid-lifetime 2592000 } reachable-time 0 retrans-timer 0 } [edit] [email protected]# sudo cat /etc/radvd.conf ### Autogenerated by service-router-advert.py ### interface br0 { IgnoreIfMissing on; AdvDefaultPreference medium; AdvManagedFlag on; MaxRtrAdvInterval 60; AdvReachableTime 0; AdvIntervalOpt on; AdvSendAdvert on; AdvOtherConfigFlag off; AdvRetransTimer 0; AdvCurHopLimit 64; prefix 2001:db8::/64 { AdvAutonomous on; AdvValidLifetime 2592000; AdvOnLink on; AdvPreferredLifetime 14400; }; }; [edit] [email protected]# show interfaces bridge br0 address 192.0.2.1/24 address 2001:db8::1/64 aging 300 description LAN firewall { local { name lan-local } } hello-time 2 ipv6 { dup-addr-detect-transmits 2 } max-age 20 member { interface eth0 { } interface eth1 { } interface eth2 { } interface eth4 { } } priority 20480 stp [edit]