$ ping6 2a02:8011:7003:1::1
PING 2a02:8011:7003:1::1 (2a02:8011:7003:1::1): 56 data bytes
ping6: sendmsg: No route to host
ping: wrote 2a02:8011:7003:1::1 64 chars, ret=-1
--- 2a02:8011:7003:1::1 ping statistics ---
1 packets transmitted, 0 packets received, 100.0% packet loss
The default route is present and pointing to 2a02:8011:7003:1::1,
but ndp for that address is showing as expired.
$ ndp -an
Neighbor Linklayer Address Netif Expire S Flags
2a02:8011:7003:1::1 00:0d:b9:41:7e:48 vlan2 expired P R 3
2a02:8011:7003:1:20d:93ff:fe63:da5a 00:0d:b9:14:30:ec vlan2 23h45m30s S
2a02:8011:7003:1:4c5:3773:8878:f8e9 00:0d:b9:14:30:ec vlan2 14h30m52s S
2a02:8011:7003:1:9446:5c90:a2b0:d2ec 00:0d:b9:14:30:ec vlan2 23h45m35s S
2a02:8011:7003:1:fab1:56ff:feac:3276 f8:b1:56:ac:32:76 vlan2 permanent R l
2a02:8011:7003:3::1 00:0d:b9:41:7e:48 vlan5 23h47m46s S R
2a02:8011:7003:3:fab1:56ff:feac:3276 f8:b1:56:ac:32:76 vlan5 permanent R l
fe80::fab1:56ff:feac:3276%vlan2 f8:b1:56:ac:32:76 vlan2 permanent R l
fe80::fab1:56ff:feac:3276%vlan4 f8:b1:56:ac:32:76 vlan4 permanent R l
fe80::fab1:56ff:feac:3276%vlan5 f8:b1:56:ac:32:76 vlan5 permanent R l
Other machines on the subnet are able to resolve and ping6
2a02:8011:7003:1::1 and beyond. (those machines are on older snaps).
Trying to remove the old ndp entry with ndc -d <addr> or ndp -c reports
that it has been deleted but it shows up again in ndp -a output immediately
# ndp -c; ndp -an | grep 2a02:8011:7003:1::1
2a02:8011:7003:1::1 (2a02:8011:7003:1::1) deleted
2a02:8011:7003:1::1 00:0d:b9:41:7e:48 vlan2 expired I R
Removing the default route and then the ndp entry does result in
it being removed, but adding the default route back in results in
ndp showing up as 'expired' again.
More bits below. Nothing relating to ND showing in log with nd6_debug.
Rebooting the workstation seemed to fix it, last time it happened
I tried rebooting the gateway instead and that seemed to fix it too.
Any ideas or suggestions of more things to collect next time it