RIPE, the European internet registry has started heavily rationing IPv4 addresses, meaning that the day of IPv6 only connections is fast approaching. BT don't yet support IPv6 on their connections, but I need to be able to use IPv6 to help ensure that servers are correctly set up to handle IPv6 only traffic.
So, I need to create an IPv6 over IPv4 tunnel.
This documentation details the steps to do this using Helium Electric's (free) tunnelbroker service