Docker IPv6
There are diffrent ways to support IPv6 in Docker. The easiest is to enable ipv6 on the docker host and simply use the docker proxy to forward ipv6 via ipv4 to the containers. But one disadvantage of this method is, that your container is unable to see the clients remote address. Each request seems to be send from the docker host. Especially nginx and php or a spam filter for your mailserver are depending on a correct client ip....