In order to do some useful stuff and have the ability to download applications, the BBB board must have direct access to the internet.
Decided to set up the Ethernet interface with a static IP address. Having a static address allows you to know how to access BBB all the tiem without the need to check the router for the assigned IP address. Choose a large address in order to avoid address conflict with existing assigned IP addresses. Choose and address that is easy to remember. You could also reserve this address in the router.