The Big Picture for "djbdns"

                        ,-------------------------.
                        | DNS Client Applications |
                        `-------------------------'
       Talks to address(es) listed in /etc/resolv.conf or $DNSCACHEIP
                                     ^|
                                     || queries & responses
                                     || containing complete answers
                                     |v
                 ,----------(Private IP address)---------.
                 | Forwarding proxy DNS server           |
                 | (e.g. dnscache with $FORWARDONLY set) |
                 `---------------------------------------'
    Talks to address(es) listed in $DNSCACHE_SERVICE_DIR/root/servers/*
                                     ^|
                                     || queries & responses
                                     || containing complete answers
                                     |v
                 ,----------(Private IP address)---------.
                 | Forwarding proxy DNS server           |
                 | (e.g. dnscache with $FORWARDONLY set) |
                 `---------------------------------------'
    Talks to address(es) listed in $DNSCACHE_SERVICE_DIR/root/servers/*
                                     ^|
                                     || queries & responses
                                     || containing complete answers
                                     |v
                ,-----------(Private IP address)-----------.
                | Resolving proxy DNS server               |
                |(e.g. dnscache with $FORWARDONLY not set) |
                `------------------------------------------'
     Talks to address(es) listed in $DNSCACHE_SERVICE_DIR/root/servers/*
             or in the delegations returned in partial answers
                        ^|           ^|          ^|
                        ||           ||          ||        queries & responses
                        ||           ||          ||        containing possibly partial answers
                        |v           ||          ||     (i.e. ending with delegations or aliases)
   ,--------(Public IP address)--.   ||          ||
   | content DNS servers for "." |   ||          ||
   |      (e.g. tinydns)         |   ||          ||
   `-----------------------------'   ||          ||
      databases contain referrals    ||          ||
            pointing to              |v          ||
           ,----------(Public IP address)--.     ||
           | content DNS servers for TLDs  |     ||
           | ("com.", "uk.", "moon.", &c.) |     ||
           |       (e.g. tinydns)          |     ||
           `-------------------------------'     ||
                  databases contain referrals    ||
                       pointing to               |v
                         ,------------(Public IP address)---------.
                         | content DNS servers for 2LDs and below |
                         | (e.g. tinydns, walldns, rbldns)        |
                         `----------------------------------------'