During the transition period from IPv4 to IPv6, there are going to be occasions where two hosts on a network are configured with IPv6 addresses, but the intervening hosts and routers are part of an IPv4 network. This section describes how to use a tunnel to overcome this problem.
What Is an IPv6-Over-IPv4 Tunnel?
An IPv6-over-IPv4 tunnel is a mechanism by which IPv6 datagrams can be transported over an IPv4 network. The sender and the receiver both support IPv6 (and IPv4), but the hosts and routers along the path the datagram takes support only IPv4. As an example, consider encryption as an analogy. Only the sender and the intended recipient know how to get at the data, such as your credit card details. While this sensitive ...