> Check ip neigh output. Does the entry for your default gateway go > STALE after those 20 minutes?
Yes, exactly: # ip -6 nei fe80::1 dev eth0 lladdr 0c:86:10:ed:31:ca router STALE > Also check the lifetime of any SLAAC ip addresses given in ip addr > output. forever > Do you really need to meddle with the fe80::1 route? I had no plans to do so. I just learned during debugging that this would reestablish IPv6 connectivity without reboot. > Do you really > need an explicit route for fe80::1%eth0? Will it work without? My hosters docs (Hetzner) recommend that. They don't specify an IPv6 default gateway. > Does adding a route for 2000/3 via fe80::1 dev eth0 help, nope (just tried it) > or is it > really necessary to remove the default route and to re-add it? yep, connectivity is back > No need, an fe80::/64 IP address is only valid when an interface is > added: [...] > Is the other interface connected? eth1 should not play a role here at > all. I had no plans to fiddle with link-local addresses, and of course eth1 settings should not matter. I just disabled IPv6 on eth1 for debugging, and suddenly IPv6 worked >20min. Maybe coincidence rather than causality. I'd like to learn what's going on here, thanks for your comments. Olaf
