It may seem surprising that a modern service like Docker does not offer IPv6 in containers by default, especially when in a network with IPv6.

In fact, for the same reason we saw in the introductory article, since the containers are in a virtual network, they cannot be reached by the box/router distributing the IPv6 subnet.

The same phenomenon can be observed with IPv4: each container has an IPv4 in a subnet separate from the one in which our host machine is located.

With Free and Orange, when IPv6 is not disabled, the Freebox (and some Livebox) provide a /64 IPv6 range to the connected equipment. But it turns out that it is a /60 range that is available and usable by each subscriber. This represents a total of 8 addressable /64 networks. Let’s see what it can be used for and how to use it.

IPv6 reminders

Contrary to IPv4, with IPv6 one avoids making NAT, i.e. one allocates to each machine on the network an IPv6 address directly routable on Internet. Of course it is always necessary to go through the router (the box) which is then used as a simple gateway to the Internet.