@steevc The thing is most of this is an anti-pattern but the solution i've seen work is granting the container 'host' access which to me is basically running things as 'root' in the docker world.
Managing an IPV6 pool of address in docker also isn't great because then you need to update your IPtables on the network to reflect that. :-(
Since we're out of IPV4 hopefully someone will prioritize fixing some of these patterns.
RE: Docker IPV6 Guide