6in4 uses tunneling to encapsulate IPv6 traffic over explicitly-configured IPv4 links. The 6in4 traffic is sent over the IPv4 Internet inside IPv4 packets whose IP headers have the IP protocol number set to 41. https://en.wikipedia.org/wiki/6in4


“6to4” is a tunneling method that is only interesting for reaching IPv6-only services. And 6to4 makes sense only if one has a public IPv4 address. As a rule, you only need to enable “6to4” if you want to access services that are only IPv6. http://www.elektronik-kompendium.de/sites/net/1904031.htm

Create an account on https://tunnelbroker.net/

seting IP on FreeBSD

ifconfig gif0 create
ifconfig gif0 tunnel Y.Y.Y.Y
ifconfig gif0 inet6 2001:470:1c:35e::2
route -n add -inet6 default 2001:470:1c:35e::1
ifconfig gif0 up

Where Y.Y.Y.Y is the Server IPv4 Address and is your lan.

mac os X setup

ifconfig gif0 create
ifconfig gif0 tunnel
ifconfig gif0 inet6 2001:470:6c:387::2 2001:470:6c:387::1 prefixlen 128
route -n add -inet6 default 2001:470:6c:387::1