The really cool thing about this – as opposed to something like Tor or I2P – is that rather than coming up with a novel addressing scheme, it just commandeers the entire (unused[0]) fc00::/8 block of IPv6. Because of this, it is 100% compatible with every existing IPv6 application.

For bonus points, it can also tunnel IPv4 and IPv6 through the P2P network[1] much like a traditional VPN would. But unlike a traditional VPN, it is sufficient to connect to any single node of the P2P network, no need for direct connectivity to the gateway. And of course that connection doesn't have to be a UDP/IP stream over the public internet, because CJDNS can speak raw Ethernet frames[2] over any hardware interface you like.

[0] https://en.wikipedia.org/wiki/Unique_local_address [1] https://github.com/cjdelisle/cjdns/tree/master/tunnel [2] https://github.com/cjdelisle/cjdns/blob/master/doc/configure...