Miredo is an implementation of the "Teredo: Tunneling IPv6 over UDP through NATs" proposed Internet standard (RFC4380). It can serve either as a Teredo client, a stand-alone Teredo relay, or a Teredo server. It is meant to provide IPv6 connectivity to hosts behind NAT devices, most of which do not support IPv6, and not even IPv6-over-IPv4 (including 6to4).