http://www.rfc-editor.org/rfc/rfc7018.txt
RFC 7018: Auto-Discovery VPN Problem Statement and Requirements, V. Manral, S. Hanna2013-09-01T23:00:00-00:00Manual configuration of all possible tunnels is too cumbersome in many such cases. In other cases, the IP addresses of endpoints change, or the endpoints may be behind NAT gateways, making static configuration impossible. The Auto-Discovery VPN solution will address these requirements.