...
In other words, containers exist within a private network, may see each other, pull network data to whatever the host can access, but nothing outside aside from the host itself will see these servers. A good analogy is your home network behind 1 public IP given on your service provider router.. Your desktops can see each other, pull data from the Internet, but the Internet cannot see your systems.
Of course, you may expose containers to the hosts's network.
Enabling LXC DNS Resolution
...