Shim6 is a multihoming protocol that has been designed by the IETF to suit the requirements of the new version of IP, IPv6. Currently BGP is used to provide multihomed connectivity to sites, but this technique is already now responsible for part of the growth of the BGP routing tables, and it could be even worth with the very long IPv6 addresses. This presentation explains the motivations that led to the design of Shim6, and goes through its functional and security challenges. We conclude with some open research areas.