[gooderlooking]

With freelan, once the client has established a connection with any other known and accessible freelan client, a direct client-client connection can be made to anyone on the network, even if they are behind a NAT/firewall. I believe it's through a combination of tun/tap, UDP-punching, and proxying, but don't know for certain.

OpenVPN establishes a site-to-site or point-to-site VPN, but routing to the client still goes through the gateway server.

Freelan still requires a known "supernode" to broker the initial connection, but after that, they can either communicate directly or through peers.