IPv6 neighbor flaps for ISP router are occurring frequently
Date: Mon, 16 Sep 2024 20:05:39 UTC
Hello. Following the earlier thread "DHCPv6 IA_PD - how-to” I have been bringing up a new gateway router for my network. With Roy’s help, I have IPv6 working as expected, but I am seeing something that I suspect is unusual. Roy doesn’t think it’s specific to dhcpcd, as it is caused by routing changes that dhcpcd is merely reacting to. While dhcpcd is running, it repeatedly logs the following to daemon.log: Sep 16 15:55:53 logrus dhcpcd[50070]: vlan0: fe80::3e8a:b0ff:fe3e:4dce is unreachable Sep 16 15:55:54 logrus dhcpcd[50070]: vlan0: fe80::3e8a:b0ff:fe3e:4dce is reachable again Sep 16 15:55:54 logrus dhcpcd[50070]: vlan0: soliciting an IPv6 router Sep 16 15:56:25 logrus dhcpcd[50070]: vlan0: fe80::3e8a:b0ff:fe3e:4dce is unreachable Sep 16 15:56:25 logrus dhcpcd[50070]: vlan0: fe80::3e8a:b0ff:fe3e:4dce is reachable again Sep 16 15:56:25 logrus dhcpcd[50070]: vlan0: soliciting an IPv6 router Sep 16 15:56:57 logrus dhcpcd[50070]: vlan0: fe80::3e8a:b0ff:fe3e:4dce is unreachable Sep 16 15:56:58 logrus dhcpcd[50070]: vlan0: soliciting an IPv6 router Sep 16 15:56:58 logrus dhcpcd[50070]: vlan0: Router Advertisement from fe80::3e8a:b0ff:fe3e:4dce Sep 16 15:57:32 logrus dhcpcd[50070]: vlan0: fe80::3e8a:b0ff:fe3e:4dce is unreachable Sep 16 15:57:32 logrus dhcpcd[50070]: vlan0: soliciting an IPv6 router Sep 16 15:57:32 logrus dhcpcd[50070]: vlan0: Router Advertisement from fe80::3e8a:b0ff:fe3e:4dce During this same time frame, “route monitor” shows: 15:55:53.573 PID 0 delete neigh fe80::3e8a:b0ff:fe3e:4dce%vlan0 state PROBE lladdr 3c:8a:b0:3e:4d:ce iface vlan0 15:55:54.002 PID 0 add/repl neigh fe80::3e8a:b0ff:fe3e:4dce%vlan0 state REACHABLE lladdr 3c:8a:b0:3e:4d:ce iface vlan0 15:56:25.148 PID 0 delete neigh fe80::3e8a:b0ff:fe3e:4dce%vlan0 state PROBE lladdr 3c:8a:b0:3e:4d:ce iface vlan0 15:56:25.212 PID 0 add/repl neigh fe80::3e8a:b0ff:fe3e:4dce%vlan0 state REACHABLE lladdr 3c:8a:b0:3e:4d:ce iface vlan0 15:56:57.406 PID 0 delete neigh fe80::3e8a:b0ff:fe3e:4dce%vlan0 state PROBE lladdr 3c:8a:b0:3e:4d:ce iface vlan0 15:56:58.967 PID 0 add/repl neigh fe80::3e8a:b0ff:fe3e:4dce%vlan0 state REACHABLE lladdr 3c:8a:b0:3e:4d:ce iface vlan0 15:57:32.325 PID 0 delete neigh fe80::3e8a:b0ff:fe3e:4dce%vlan0 state PROBE lladdr 3c:8a:b0:3e:4d:ce iface vlan0 15:57:34.143 PID 0 add/repl neigh fe80::3e8a:b0ff:fe3e:4dce%vlan0 state REACHABLE lladdr 3c:8a:b0:3e:4d:ce iface vlan0 My concern is that this is sending RS’s to my provider far too often. Can anyone advise if this is normal, and assuming not, what might be wrong? Trimmed dhcpcd.conf is: duid persistent vendorclassid option classless_static_routes option rapid_commit require dhcp_server_identifier slaac private noipv6rs noipv4 noipv4ll allowinterfaces vlan0 interface vlan0 ipv6only ipv6rs ipv6ra_autoconf ia_pd 0/::/56 intnet1/42 intnet2/56 Thanks. - Chris