Run owncloud with access only from LAN

I’m told by a relative that he runs owncloud because it allows use within his home while not allowing external access.

Is this the default when installing owncloud, or does it require some work?

It is easy enough to configure an ownCloud instance that can only be accessed from a LAN if you understand network and server administration. You could call it the default configuration since any access from outside the network requires you to configure your network perimeter to allow access.