Relaying HTTP from IPv4 to IPv6
Cisco
As IPv6-only hosts become commonplace, it is desirable to still have IPv4 clients access those IPv6-only hosts. Due to the size of the IPv4 and IPv6 address spaces, this has proven difficult using pure IP address translation. Rather than trying to support all IP protocols, or even all TCP or UDP applications, this document proposes a mechanism for an IPv4 HTTP client to connect to an IPv6-only HTTP server.