Totd is a small DNS proxy nameserver that supports IPv6 only hosts/networks
that communicate with the IPv4 world using some translation mechanism.
Examples of such translation mechanisms currently in use are:

   * IPv6/IPv4 Network Address and Packet Translation (NAT-PT)
     implemented e.g. by Cisco.
   * Application level translators as the faithd implemented by
     the KAME project (http://www.kame.net). See faithd(8) on
     *BSD/Kame.

WWW: https://BSDforge.com/projects/dns/totd/