Named Data Networking (NDN) is a proposed information-centric design for the future Internet architecture, where application names are directly used to route requests for data. This key component of the architecture raises concerns about scalability of the forwarding system in NDN network, i.e., how to keep the routing table sizes under control given unbounded nature of application data namespaces. In this paper we apply a well-known concept of Map-and-Encap to provide a simple and secure namespace mapping solution to the scalability problem. More specifically, whenever necessary, application data names can be mapped to a set of globally routable names that are used to retrieve the data. By including such sets in data requests, we are informing (more precisely, hinting) the forwarding system of the whereabouts of the requested data, and such hints can be used when routers do not know from where to retrieve the data using application data names alone. This solution enables NDN forwarding to scale with the Internet's well-understood routing protocols and operational practice, while keeping all the benefits of the new NDN architecture.