Source: radvd Followup-For: Bug #896431 It appears my issue was not related to radvd actually.
I had two instances of dhclient and I believe, my ISP's router removed some prefix routes on their routers, after some timeout. I am certain that I dones some radvd restarts in the past and that it continued working after that for a day or less. But I think it was ultimately dhclient issue. radvd was broadcasting routes (inspected with tcpdump) all the time, so restart was not required. But again, I know for the fact that restarting radvd in the past usually helped. No idea why. I found it is dhcp issue, because I lost routing, but the default route was correct on my LAN host and tcpdump was showing everything is ok, and restarting radvd didn't help. But restarting dhcp did help. I fixed my dhcp issue with configuration, and I have no stable IPv6 routing. Please close the bug. Thanks!
