No, that was not a real problem. If you read a later post, you will see that the problem was that the client needed another configuration file. Maybe you can try playing with the file I mentioned (~/.safe/node/node_connection_info.config)
At that time I succeeded in creating a docker bridge network and a safe network with 9 nodes. Each node was a docker container in this bridge network and had its own IP address. I guess the default docker bridge network would have worked the same, I created my own only to test IPv6.
EDIT: I forgot to mention I was using Docker on Windows (with Linux containers).
But with recent limitations added by @maidsafe, all what I could do at that time doesn’t work anymore. And not just an IPv6 network, I cannot create any network (see Cannot start node 0.28.0 due to error: Routing(Network( IgdNotSupported)) - #6 by tfa).