Unbound constantly stops and restarts with new modem
This is for those experiencing problems with unbound failing after ISP replaces a modem.
Had a modem fail that is attached to a Netgate SG-4860. Contacted Spectrum/Charter which had a field tech come out and replace it. This Internet connection has one IPv4 static IP and the modem is set to bridged mode. After the modem replacement, the unbound service quit working and was constantly stopping and restarting. The CPU usage would fluctuate between 24% and 50%. The DNS Resolver logs did not seem to leave any clues except for the stop/start messages. However the firewall logs showed all kinds of IPv6 calls. To cut to the chase, ended up solving the problem by setting the IPv6 Configuration Type to None under Interfaces / WAN.
Point is, everything was working perfectly until Spectrum / Charter replaced the modem, with a newer model, which caused unbound to fail. Changing the aforementioned solved the problem.