Utilize o script abaixo para poder inspecionar as conexões do container. Execute no hospedeiro.
docker inspect --format '{{.State.Pid}} {{printf "%.13s" .ID}} {{.Name}}' \
$(docker ps --format '{{.ID}}') | while read dockpid dockid dockname
do
echo $dockid $dockname
sudo nsenter -t $dockpid -n netstat -vantup
done