IPv6 Connectivity Check and Redirection by HTTP Servers
Cisco Systems
Rather than forcing the client to decide whether IPv4 or IPv6 is more convenient to reach a web server; this document proposes to let the web server check whether there is IPv6 connectivity to the client; then the web server can do a HTTP redirect to the force the client to use IPv6. This is done easily by a script within the server HTML pages and does not require any change in the client applications or configuration. The client still can control whether he/she wants to enabled IPv6. This draft could be discussed on the Applications Discuss mailing list, https://www.ietf.org/mailman/listinfo/apps-discuss.