I would like to start by telling you I am by no means a Docker expert, so I may just be looking at this in the wrong way.
Anyway, my issue is as followed:
One of my compose containers has to read data from an external container (etcd). When this container is launched within the docker-compose.yml and linked to there is no issue (“etcd:2379” is accessible as a host). As soon as I externalize the etcd container (start it from outside the compose file) and replace the link with an external link ("- etcd:etcd") networking no longer works.
If you would like to see a docker-compose.yml please ask.