The mapping of IPv4 and IPv6 addresses to names using the Domain Name System (DNS) is colloquially known as "Reverse Mapping". Reverse Mapping support for registered multicast address assignments in IPv4 is currently incomplete and ad-hoc; in IPv6 there is no support at all.
This document describes procedures to be followed that will result in more systematic and predictable support for Reverse Mapping for IPv4 multicast address assignments, and introduces analogous support for IPv6.