Router Advertisement DNS (radns)

radns is an IPv6 DNS server address autoconfiguration client. It
listens for IPv6 Router Advertisements with the Recursive DNS Server
(RDNSS) and the DNS Search List (DNSSL) options and stores the search
list and address(es) in a file in the same syntax as resolv.conf(5).

WWW: http://hack.org/mc/hacks/radns/