While, on the one hand, the huge address space of IPv6 makes it possible to solve the addressing issues in IoT; on the other hand, it introduces overheads that are not compatible with the scarce capabilities of constrained nodes. This problem can be overcome by adopting 6LoWPAN [25], [26], which is an established compression format for IPv6 and UDP headers over low-power constrained networks. A border router, which is a device directly attached to the 6LoWPAN network, transparently performs the conversion between IPv6 and 6LoWPAN, translating any IPv6 packet intended for a node in the 6LoWPAN network into a packet with 6LoWPAN header compression format, and operating the inverse translation in the opposite direction.While the deployment of a 6LoWPAN border router enables transparent interaction between IoT nodes and any IPv6 host in the Internet, the interaction with IPv4-only hosts remains an issue. More specifically, the problem consists in finding a way to address a specific IPv6 host using an IPv4 address and other meta-data available in the packet. In the following, we present different approaches to achieve this goal.